SECONDARY AUTOGENIC SUCCESSION IN THE SOUTHERN ROCKY MOUNTAIN TRENCH by JOHN BRYAN KEMPER B. Sc., U n i v e r s i t y o f B r i t i s h Columbia, 1 9 6 7 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e Department of Plant Science We a c c e p t t h i s t h e s i s as conforming t o t h e required standard THE UNIVERSITY OF BRITISH COLUMBIA APRIL, 1971 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make i t freely ava i lable for reference and study. I further agree that permission for extensive copying of this thesis for scholarly, purposes may by his representatives. be granted by the Head of my Department or It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of B r i t i s h Columbia Vancouver 8, Canada Date /, //// 1i Frontpiece: P r e m i e r R i d g e , one o f s e v e r a l c r i t i c a l w i n t e r ranges f o r w i l d u n g u l a t e s , which e x i s t on t h e f l o o r o f t h e s o u t h e r n Rocky Mountain Trench. The western edge o f the Rocky Mountains, Hughes Ranges, may he seen on t h e r i g h t o f the p i c t u r e . Iii ABSTRACT SECONDARY AUTOGENIC SUCCESSION IN THE SOUTHERN ROCKY MOUNTAIN TRENCH The p a t t e r n s and r a t e s o f f o r e s t r e g e n e r a t i o n on a c r i t i c a l w i l d l i f e w i n t e r range on t h e f l o o r o f t h e t r e n c h , known l o c a l l y as Premier Ridge were examined i n t h i s study. gated A nearby w e s t e r n w a l l o f t h e t r e n c h was a l s o I n v e s t i t o a s c e r t a i n t h e e f f e c t o f e l e v a t i o n on f o r e s t r e - g e n e r a t i o n and u n d e r s t o r y p r o d u c t i v i t y . Forest regeneration i n a community which has remained u n f o r e s t e d f o r s e v e r a l ' as y e a r s has pronounced e f f e c t s on t h e f l o r i s t i c p r o d u c t i v i t y of the understory. est floristic corresponding dynamics and On Premier Ridge t h e g r e a t - change was a r a p i d i n c r e a s e i n p i n e g r a s s and a. d e c r e a s e i n t h e abundance o f a l l o t h e r s p e c i e s as t h e f o r e s t r e g e n e r a t i o n p r o g r e s s e d . grass Forbs v a r i e d w i d e l y I n abundance w h i l e shrubs were s l o w e r t o r e a c t t o changes i n t h e o v e r s t o r y . S i m i l a r t r e n d s were observed on E s t e l l a Mountain. P r o d u c t i v i t y o f t h e g r a s s component on t h e unf o r e s t e d s i t e s was f o u r times t h a t o f t h e f o r e s t e d s i t e s . The p r o d u c t i o n o f f o r b s and some s p e c i e s o f shrubs a l s o dec l i n e d as f o r e s t regrowth began. One s p e c i e s , b e a r b e r r y , i n c r e a s e d under l i g h t f o r e s t c a n o p i e s . The r e d u c t i o n i n p r o d u c t i v i t y and t h e changes i n s p e c i e s c o m p o s i t i o n o f - t h e u n d e r s t o r y which o c c u r i n regenera t i n g f o r e s t communities, appear t o be d e t r i m e n t a l t o f o r a g i n g iv populations o f w i l d and to p r e f e r to graze generation use proceeds, diminishes. s t o c k numbers overgrazing the forest quantity. diet the domestic ungulates. open, u n f o r e s t e d Since t h e r e h a v e b e e n few as readily reductions The component most o f t h e w i l d l i f e in during q u i c k l y e l i m i n a t e d by w h i c h may be under f o r e s t the winter forest u s e d by wildlife cover. This to of. species using summer by is local by and the In a d d i t i o n , b i t t e r b r u s h , u s e d and in regrowth Premier Ridge area. cattle re- i n terms o f q u a l i t y I s t h e most i m p o r t a n t o f c a t t l e and and range shrinkage, become more w i d e s p r e a d . r e d u c e s 'the g r a s s , b o t h This areas, the acreage which they w i l l t o compensate f o r t h i s has C a t t l e seem the in the b i g game s p e c i e s , regeneration. Bearberry, some e x t e n t , component does n o t increases approach i n -a value or usefulness, represent to g r a z i n g The are the on t r e e s of the these south relatively slopes areas a r e more f a v o u r a b l e are less but may on should u s e d as and southwestern aspects slow growth r a t e s . f u t u r e economy o f t h e remain t r e e l e s s . the n o r t h f r e q u e n t l y used as be components i s modest; i f g r a z i n g a r e deemed d e s i r a b l e i n t h e Kootenay, these other animals. c h a r a c t e r i z e d by production l o s s e s that the and northeast f o r a g i n g areas s h e l t e r or bedding by areas. Forage animals East Growth • rates aspects, winter which wildlife, V TABLE OP CONTENTS Page I INTRODUCTION A. B. C. II Area Description Climate . The P r o b l e m METHODS AND A. B. C. D. Criteria for Site Selection S i t e D e s c r i p t i o n Techniques Determination of Characteristic S t a n d Age Annual P r o d u c t i v i t y Assessments 4. OBSERVATIONS AND A. Timber.... B i t t e r b r u s h and S o a p o l a l l i e . G r a s s e s , F o r b s and D w a r f Shrubs Bearberry 2. 3. 4. 5. Skookumchuck P r a i r i e The N a t u r a l G r a s s l a n d . . . Premier Ridge Non-forested Sites Premier Ridge Forested Sites E s t e l l a Mountain Forested Sites E s t e l l a Mountain - Floristic 2. 15 17 17 18 20 20 22 Non-forested Sites 1. 11 13 RESULTS Site Descriptions 1. B. 2 8 9 MATERIALS 1. 2. 3. III and H i s t o r y 23 25 3 1 42 49 5^ Dynamics Premier Ridge S i t e s 5^ a. b. Grasses Forbs 56 57 c. Shrubs 60 E s t e l l a Mountain a. b. c. Grasses Forbs Shrubs Sites 60 6C 67 P7 1 vi C. Page 1. E. F. G. P r e m i e r Ridge... E s t e l l a Mountain, ' 73 75 75 77 . 80 80 80 83 83 85 85 85 85 85 87 S i t e H i s t o r y and Paths o f S u c c e s s i o n on P r e m i e r Ridge .. 92 S i t e H i s t o r y and Paths o f S u c c e s s i o n on E s t e l l a . Mountain 95 P r o d u c t i v i t y o f the Forest, 1. 2. H. Porb P r o d u c t i v i t y . . . . . . . Dwarf Shrub Productivity d. B e a r b e r r y Productivity e. Bitterbrush Productivity f. So&polallie Productivity... E s t e l l a Mountain a. Grass P r o d u c t i v i t y b. Forb P r o d u c t i v i t y c. Dwarf Shrub Productivity d. B e a r b e r r y Productivity e. Bitterbrush Productivity f. Soapolallie Productivity O v e r s t o r y Community C o m p o s i t i o n . . . . 1. 2. 71 Grass P r o d u c t i v i t y t>. c. 2. 7± P r e m i e r Ridge a. D. 71 Productivity P r e m i e r Ridge , E s t e l l a Mountain..., Aggregate U n d e r s t o r y P r o d u c t i v i t y . . 1. 2. Premier Ridge... E s t e l l a Mountain 104 '10k 106 108 108 113 vii LIST OP TABLES Page I The I n f l u e n c e o f c h a r a c t e r i s t i c s t a n d age on the s p e c i e s dynamics o f t h e u n d e r s t o r y g r a s s species 59 The i n f l u e n c e o f f o r e s t canopy on t h e p e r c e n t ground c o v e r o f t h e g r a s s component o f t h e understory 59 The abundance o f shrubs on the P r e m i e r Ridge s i t e s , i n r e l a t i o n to c h a r a c t e r i s t i c stand age and f o r e s t canopy 66 The abundance o f s e v e r a l s p e c i e s o f g r a s s e s as measured by p e r c e n t ground c o v e r on E s t e l l a Mountain 69 V The abundance o f f o r b s as measured b y p e r c e n t ground c o v e r on E s t e l l a Mountain 70 VI S t a t i s t i c s f o r shrub abundance on E s t e l l a Mountain VII S i t e s t: a t i s t i c s f o r t r e e s , P r e m i e r R i d g e , VIII Site s t a t i s t i c s for trees, Estella IX S t a t i s t i c s f o r stumps, P r e m i e r R i d g e , 1969 9'6 X F o r e s t c o v e r o f P r e m i e r Ridge s i t e s , p a s t and present 97 XI The paths o f s u c c e s s i o n on P r e m i e r Ridge 98 XII S t a t i s t i c s f o r stumps, E s t e l l a Mountain, 1969. 99 XIII F o r e s t c o v e r o f E s t e l l a Mountain, p a s t and II III IV 1969.. 1969 , Mountain, present XIV The paths o f s u c c e s s i o n on E s t e l l a Mountain XV S t a t i s t i c s r e l a t i n g t o wood p r o d u c t i o n , P r e m i e r Ridge s i t e s . . . . 71 91 93 • 100 102-103 •••105 viii XVI XVII XVIII Page Statistics relating to wood production, Estella Mountain sites 107 The aggregate annual understory productivity on Premier Ridge. 112 The aggregate annual understory productivity on Estella Mountain 116 ix LIST OP FIGURES Page 1. Map o f t h e Premier Ridge s t u d y a r e a 3 2. Map o f t h e E s t e l l a Mountain s t u d y a r e a 4 3. I l l u s t r a t i o n of the d e t e r m i n a t i o n of c h a r a c t e r i s t i c s t a n d age l6 4. The Skookumchuck P r a i r i e , a n a t u r a l g r a s s l a n d . 24 5. The b l u e g r a s s - n e e d l e g r a s s p l o t , l o c a t e d A l k a l i Lake near 26 ; 6. The b l u e g r a s s - n e e d l e g r a s s e x c l o s u r e 27 7. The b i t t e r b r u s h s i t e 29 8. A close-up of the b i t t e r b r u s h e x c l o s u r e 30 9. The r e l i c t wheatgrass s i t e 32 10. R e g e n e r a t i o n on t h e s t e e p w e s t e r n a s p e c t s has been slow 34 11. The 34 12. The young Douglas f i r . s i t e 35 13. The middle-aged 37 14. The mature Douglas f i r s i t e 38 15. The young ponderosa p i n e s i t e . . 4-.1 16. The middle-aged 44 17. A c l o s e - u p o f the middle-aged " t e r r a c e " a r e a o f Premier. Ridge Douglas f i r s i t e ponderosa p i n e s i t e ponderosa p i n e site 44 18. The c l i m a x ponderosa p i n e s t a n d 45 19. The l o d g e p o l e p i n e s t a n d on Premier Ridge 46 20. The r e g e n e r a t i n g Douglas f i r s t a n d on E s t e l l a Mountain 48 , X Page 21. The l a r c h stand 22. The l o d g e p o l e p i n e s t a n d on E s t e l l a 50 Mountain 51 23. The s e r a i f e s c u e s i t e 53 24. 25. The s e r a i wheatgrass s i t e The abundance o f s e v e r a l s p e c i e s o f g r a s s e s on P r e m i e r Ridge as I n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. 55 58 The abundance o f s e v e r a l s p e c i e s o f f o r b s on Premier Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age 6l The abundance o f s e v e r a l s p e c i e s o f f o r b s on Premier Ridge as i n f l u e n c e d by f o r e s t canopy. 62 The abundance o f t i m b e r m i l k v e t c h and BaIsammo r h i z a s a . g i t t a t a on Premier Ridge as i n f l u e n c e d by f o r e s t canopy 63 The abundance o f f o r b s on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy 64 The abundance o f dwarf shrubs on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy 65 The abundance o f s e v e r a l s p e c i e s o f g r a s s e s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy 68 26. 27. 28. 29. 30. 31. 32. 33. The abundance o f f o r b s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy ' • 72 The p r o d u c t i v i t y o f g r a s s on Premier Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c stand age and f o r e s t canopy 74 The p r o d u c t i v i t y o f g r a s s on Premier R i d g e as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The a n n u a l p r o d u c t i v i t y o f dwarf shrubs on Premier Ridge as I n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy... The a n n u a l p r o d u c t i v i t y o f b e a r b e r r y on Premier Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The a n n u a l p r o d u c t i v i t y o f b i t t e r b r u s h ( t w i g s a n d j t h e i r l e a v e s o n l y ) on Premier R i d g e as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The a n n u a l p r o d u c t i v i t y o f s o a p o l a l l i e ( t w i g s and l e a v e s ) as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The p r o d u c t i v i t y o f g r a s s e s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. The p r o d u c t i v i t y o f f o r b s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The p r o d u c t i v i t y o f dwarf shrubs on E s t e l l a Mountain a.s i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy The a n n u a l p r o d u c t i v i t y o f b e a r b e r r y on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy : The a n n u a l p r o d u c t i v i t y o f s o a p o l a l l i e ( t w i g s and l e a v e s ) as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy, E s t e l l a s i t e s . . . I n e aggregate a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f Premier Ridge as i n f l u e n c e d by f o r e s t canopy. xii Page 45. 46. 47. The aggregate a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age......... I l l The aggregate a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age 11.4 The aggregate a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a Mountain as i n f l u e n c e d by f o r e s t canopy 115 xiv (A.e.- -*.v\v) ACKNOWLEDGEMENTS I would l i k e t o thank Dr. V. C. B r i n k f o r h i s c o n t i n u i n g encouragement and t h o u g h t f u l g u i d a n c e . Dr. B r i n k , Dr. P. J . Bandy and Dr. I . McTaggart Cowan v i s i t e d t h e study a r e a and made many h e l p f u l s u g g e s t i o n s . Valuable criticism was p r o v i d e d by o t h e r members o f my committee, i n c l u d i n g Dr. W. D. K i t t s and Dr. L. M. L a v k u l i c h . Ray Demarchi and s t a f f o f t h e Cranbrook o f f i c e o f t h e P i s h and W i l d l i f e Branch a s s i s t e d t h i s p r o j e c t i n many ways; w i t h t h e i r and cooperation t h a t o f t h e B. C. F o r e s t S e r v i c e , t h e p r o j e c t went smoothly. The F i s h and W i l d l i f e Branch supported work i n t h e summers o f 1968 and 1969 and t h e i r the f i e l d financial a s s i s t a n c e was g r e a t l y a p p r e c i a t e d . Mr. summer o f 1969 R i c k Howie s e r v e d as f i e l d a s s i s t a n t i n t h e and h i s h e l p was much a p p r e c i a t e d . The measure o f c o o p e r a t i o n which was a c h i e v e d with the B.' C. F o r e s t S e r v i c e , t h e B. C. F i s h and W i l d l i f e Branch and the l o c a l ranchers and c i t i z e n s was most g r a t i f y i n g . 1 INTRODUCTION Recent changes i n t h e p o p u l a t i o n s o f d e e r , e l k and b i g h o r n sheep i n t h e E a s t Kootenay r e g i o n have been l i n k e d to changes i n t h e v e g e t a t i o n o f t h e c r i t i c a l w i n t e r ranges, brought about by l o g g i n g , b u r n i n g and g r a z i n g by domestic animals. Widespread l o g g i n g and b u r n i n g o f t h e montane f o r e s t s on t h e f l o o r o f t h e s o u t h e r n Rocky Mountain Trench a t t h e t u r n o f t h e c e n t u r y removed almost a l l t h e mature f o r e s t s a t low e l e v a t i o n s . The removal o f t h e f o r e s t o v e r s t o r y I n i t i a t e d t h e development o f s e r a i communities dominated by g r a s s e s , f o r b s and s h r u b s ; t h e r e s u l t was an increase i n forage f o r ungulates. Small l o c a l populations o f t h e l a r g e u n g u l a t e s , e l k , b i g h o r n sheep, mule deer and w h i t e - t a i l e d d e e r , p r e v i o u s l y c o n s i d e r e d n o t t o be abundant, responded t o t h i s expanding d i s t r i b u t i o n and numbers. food s u p p l y by i n c r e a s i n g E a r l y s e t t l e r s i n the area advantage o f t h i s young s e r a i v e g e t a t i o n t o r a i s e their took livestock. S i n c e 1 9 3 0 f o r e s t f i r e s have been uncommon i n t h e s o u t h e r n Rocky Mountain Trench, and f o r e s t r e g e n e r a t i o n on the logged and burned a r e a s has been r a p i d . r a t e s o f domestic Heavy s t o c k i n g c a t t l e on those a c r e s c o n s i d e r e d as c r i t i - c a l w i n t e r ranges f o r w i l d u n g u l a t e s i s t a x i n g t h e e x i s t i n g range r e s o u r c e . A r e c e n t d i e - o f f i n Rocky Mountain b i g h o r n 2 sheep has f o c u s e d a t t e n t i o n on t h e problem, r e s u l t i n g i n the i n i t i a t i o n o f range and a n i m a l - o r i e n t e d r e s e a r c h t o examine the problem and suggest ways o f p r e v e n t i n g i t s r e c u r r e n c e . T h i s s t u d y was 1. determine: The p a t h and r a t e s o f s u c c e s s i o n o f t h e vegetat ion. 2. i n i t i a t e d to -^'g? >«;^^ The e f f e c t o f t r e e r e g e n e r a t i o n on the floristic c o m p o s i t i o n o f the u n d e r s t o r y . 3. The e f f e c t o f f o r e s t r e g e n e r a t i o n on the a n n u a l understory p r o d u c t i v i t y . 4. The i n f l u e n c e of t h e c u r r e n t g r a z i n g p r a c t i c e s on t h e open s e r a i r a n g e l a n d s . The w i n t e r range s e l e c t e d f o r i n t e n s i v e study Premier Ridge and a d j a c e n t E s t e l l a Mountain. was A s e r i e s of e x c l o s u r e p l o t s were e s t a b l i s h e d under the v a r i o u s types of secondary and c l i m a x f o r e s t s which e x i s t i n the a r e a . Three p l o t s were e s t a b l i s h e d on open communities which have f a i l e d t o r e g e n e r a t e t o f o r e s t a f t e r l o g g i n g which about 1910. occurred One p l o t on a n a t u r a l g r a s s l a n d , l o c a t e d near the s t u d y area,.was i n c l u d e d i n t h e s t u d y f o r comparative purposes. A. Area D e s c r i p t i o n and H i s t o r y The s o u t h e r n Rocky Mountain Trench i n t h e east Kootenay r e g i o n l i e s i n the s o u t h e a s t c o r n e r o f B r i t i s h Columbia, bounded by the A l b e r t a b o r d e r on the e a s t , the Key t o t h e s i t e s on P r e m i e r R i d g e . 1 Mature Douglas f i r 2 Young Douglas f i r 3 Bitterbrush 4 Poa - S t i p a u n f o r e s t e d 5 M i d d l e - a g e d ponderosa p i n e 6 Bluebunch wheatgrass u n f o r e s t e d 7 Young ponderosa p i n e 8 M i d d l e - a g e d Douglas f i r 9 C l i m a x ponderosa p i n e (Purshia) unforested Key t o the sites 1 R e g e n e r a t i n g Douglas f i r 2 Larch 3 Serai 4 Lodgepole P i n e fescue 5 ' S e r a i bluebunch wheatgrass 4 Estella Mountain SCALE 150,000 e '~ Montana b o r d e r on the s o u t h and t h e P u r e e l l Mountains the west. on The n o r t h e r n boundary o f the " s o u t h e r n t r e n c h " i s l o c a t e d i n the v i c i n i t y o f C a n a l F l a t s , B r i t i s h Columbia. S o i l s u r v e y s and g e o l o g i c a l d a t a f o r t h e a r e a have been r e c o r d e d by K e l l e y and Sprout ( 1 9 5 6 ) and G. G. Runka (1970). The h i s t o r y o f t h e E a s t Kootenay r e g i o n c e n t r e s a.bout the e x p l o i t a t i o n o f i t s n a t u r a l r e s o u r c e s , f u r s , m i n e r a l s and a r a b l e l a n d s . B e f o r e the advent of white man, I n d i a n s g r a z e d h o r s e s on the s c a n t y n a t u r a l g r a s s l a n d s which e x i s t e d on the t r e n c h f l o o r , ( K e l l e y and Sprout 1 9 5 6 ) . Early e x p l o r e r s i n 1807 n o t e d t h a t the K o o t e n a i I n d i a n s were "a s c r u f f y l o t " but t h a t t h e y p o s s e s s e d horses. exceptionally fine These e x p l o r e r s a l s o n o t e d the absence o f b i g game i n t h e a r e a , s t a t i n g t h a t food was difficult to o b t a i n . Another f a c t which f u r t h e r r e v e a l s the s c a r c i t y o f l a r g e u n g u l a t e s i s t h a t the K o o t e n a i I n d i a n s were o b l i g e d t o make two a n n u a l f o r a y s t h r o u g h t h e Crowsnest Pass i n t o the p l a i n s to hunt b i s o n . These a n i m a l s were p r o b a b l y t h e i r o n l y s t a b l e meat s o u r c e f o r much o f the y e a r . In the e a r l y l 8 0 0 ' s the f u r t r a d e was about 50 y e a r s , g i v i n g way active for t o a g o l d r u s h on t h e W i l d h o r s e R i v e r ( t h e n c a l l e d the Stud Horse R i v e r ) i n 1 8 6 3 . The demand f o r meat i n the m i n i n g camps p r o b a b l y e x e r t e d moderate p r e s s u r 6 on t h e r e l a t i v e l y s m a l l p o p u l a t i o n s o f w i l d u n g u l a t e s which existed i n the area a t that time. C a t t l e were few i n t h e a r e a u n t i l 1890 a t which time s e v e r a l r a n c h e r s had developed herds o f 200 t o 300 head ( K e l l e y and Sprout 1956). E a r l y l o g g i n g r e c o r d s have proven d i f f i c u l t t o obtain f o r t h i s area. A p p a r e n t l y t h e e a r l i e s t m i l l s opened about. 1 8 8 4 , and by 1910 r a i l w a y l o g g i n g was b e i n g p r a c t i c e d on t h e t r e n c h f l o o r . S l a s h f i r e s and a c c i d e n t a l f i r e s were common f o l l o w i n g l o g g i n g . V i r t u a l l y a l l o f t h e bottom l a n d s o f t h e t r e n c h f l o o r were f i r e d one o r more t i m e s . The o r i g i n a l f o r e s t c o v e r o f t h e t r e n c h f l o o r was predominately a mature Montane F o r e s t o f ponderosa p i n e (Pinus ponderosa) and Douglas f i r (Pseudotsuga m e n z i e s i i v a r . g l a u c a ) o c c u r r i n g i n mixed stands w i t h o c c a s i o n a l pure stands o f e i t h e r s p e c i e s . B l a c k cottonwood t r i c h o c a r p a ) a.nd Englemann spruce (Populus ( P i c e a engelmanni) were common i n m o i s t draws and a l o n g r i v e r channels. On t h e e a s t e r n w a l l o f t h e t r e n c h , Douglas f i r p r e s e n t l y predominates; ponderosa p i n e i s more abundant. on t h e d r i e r east w a l l and t r e n c h f l o o r , o c c u r r i n g t o a . • maximum e l e v a t i o n o f 4 , 0 0 0 f t . Above t h i s elevation, Englemann spruce d i s p l a c e s Douglas f i r on t h e more m o i s t n o r t h and n o r t h e a s t a s p e c t s . Western l a r c h ( L a r i x o c c i - d e n t a l ! s ) i s a r u d e r a l and i s common i n m o i s t locations. At a l l e l e v a t i o n s , n o r t h and n o r t h e a s t s l o p e s a r e more 7 h e a v i l y t i m b e r e d than t h e i r s o u t h and southwest parts. Lodgepole p i n e ( P i n u s c o n t o r t a v a r . counter- latifolia) occurs s p o r a d i c a l l y , at a l l e l e v a t i o n s , u s u a l l y f o l l o w i n g fire. N a t u r a l g r a s s l a n d s a r e r e s t r i c t e d t o d r y benches of the t r e n c h f l o o r where Bluebunch wheatgrass (Agropyron s p i c a t u m ) and rough f e s c u e ( F e s t u c a s c a b r e l l a ) were once the dominant s p e c i e s . However, heavy g r a z i n g p r e s s u r e by domestic s t o c k reduced or e l i m i n a t e d t h e bunchgrasses re- p l a c i n g them w i t h s p a r c e stands o f p e r e n n i a l Poa and Stipa, and a n n u a l g r a s s e s and weeds which p r e s e n t l y c o n s t i t u t e the main c o v e r . E r r a t i c l o g g i n g and b u r n i n g on the t r e n c h f l o o r has l e f t a complex v e g e t a t i o n a l p a t t e r n o f secondary w i t h o c c a s i o n a l open s e r a i and n a t u r a l g r a s s l a n d s . forests On l i m i t e d a c r e a g e s , u s u a l l y on s o u t h o r soxathwest s l o p e s , p r e v i o u s l y logged a r e a s have not y e t r e g e n e r a t e d t o f o r e s t cover. A c o m b i n a t i o n of e n v i r o n m e n t a l f a c t o r s c o u p l e d w i t h heavy g r a z i n g p r e s s u r e by b o t h w i l d and domestic may be r e t a r d i n g f o r e s t r e g e n e r a t i o n . ungulates Many o f these open areas a r e regarded as c r i t i c a l w i n t e r ranges f o r w i l d ungulates. An a c t i v e C h r i s t m a s t r e e i n d u s t r y i s p r a c t i c e d i n s e v e r a l a r e a s ; t h e t r e e s a r e cut so they w i l l regrow. V i r t u a l l y a l l o f the open and semi-open r a n g e l a n d 8 o f the t r e n c h f l o o r i s g r a z e d by c a t t l e and many o f these areas support some w i n t e r i n g n a t i v e u n g u l a t e s from December to May. In ea.rly s p r i n g , a r a b l e l a n d s a r e a l s o used by n a t i v e game a n i m a l s . B. Climate The c l i m a t e o f the s o u t h e r n Rocky Mountain Trench i s sub-humid w i t h an a n n u a l p r e c i p i t a t i o n o f 14 - 20 i n c h e s per y e a r . Much o f t h i s f a l l s as snow d u r i n g the w i n t e r months from November t o F e b r u a r y , a l t h o u g h a secondary i n p r e c i p i t a t i o n o c c u r s i n June. The peak s p r i n g thaw u s u a l l y p r o v i d e s adequate s o i l m o i s t u r e f o r growth, b e i n g r e i n f o r c e d by the June r a i n s ( K e l l e y and Sprout 1956). The d i f f e r e n c e between good and poor growing y e a r s i s r e l a t e d t o the June precipitation. D u r i n g the summer o f 1 9 6 9 , when most o f the p r o d u c t i v i t y samples were t a k e n , the June p r e c i p i t a t i o n was remarkably h i g h (about 7 " ) . Hence t h e v a l u e s f o r p r o - d u c t i o n s h o u l d be c o n s i d e r e d as maximal r a t h e r than average. Summer c o n v e c t i v e and o r o g r a p h i c p r e c i p i t a t i o n extend the growing temperatures season on t h e t r e n c h f l o o r . 100° High summer on the t r e n c h f l o o r , p a r t i c u l a r l y on south southwest s l o p e s where ambient a i r temperatures f l o o r above 4,000 The and exceeding F a r e sometimes r e c o r d e d , s e v e r e l y l i m i t the ness o f summer p r e c i p i t a t i o n . may effective- east w a l l o f t h e t r e n c h f t . i s c o o l e r and r e c e i v e s more f r e q u e n t 9 r a i n f a l l throughout t h e y e a r from p r e v a i l i n g w e s t e r l y weather systems. K e l l e y and Sprout ( 1 9 5 6 ) r e p o r t e d t h a t t h e growing season on the t r e n c h f l o o r was a p p r o x i m a t e l y 180 days, from A p r i l 15 t o e a r l y October. At h i g h e r e l e v a t i o n s the growing season i s c o r r e s p o n d i n g l y s h o r t e r , but c o o l e r summer t e m p e r a t u r e s p e r m i t almost c o n t i n u o u s growth. On the t r e n c h f l o o r dormancy i n g r a s s e s and f o r b s o c c u r s about the second week i n J u l y . C. The Problem F o l l o w i n g e x t e n s i v e l o g g i n g and b u r n i n g on t h e t r e n c h f l o o r e a r l y i n t h e t w e n t i e t h c e n t u r y , b i g game p o p u l a t i o n s i n c r e a s e d , r e s p o n d i n g t o the i n c r e a s e d fora,ge made a v a i l a b l e by man's a l t e r a t i o n o f t h e h a b i t a t . A second s e r i e s o f f i r e s e a r l y i n t h e t h i r d decade d e s t r o y e d many o f the young f o r e s t s w h i c h had begun t o r e - e s t a b l i s h on t h e t r e n c h f l o o r . Ranchers took advantage o f t h i s new range r e s o u r c e by i n c r e a s i n g t h e s t o c k i n g r a t e s o f domestic c a t t l e and h o r s e s . The numbers o f l a r g e w i l d u n g u l a t e s remains h i g h e r than t h o s e r e c o r d e d p r e v i o u s l y , however a g r a d u a l d e c l i n e has been noted s i n c e 19^5* as t r e e s once a g a i n b e g i n t o be predominant o v e r the t r e n c h f l o o r . The i n s t i t u t i o n o f v e r y e f f e c t i v e f i r e p r o t e c t i o n f o r the young f o r e s t s has r e s u l t e d i n a c o n t i n u a l s h r i n k i n g o f open range a c r e a g e . Stocking 10 r a t e s i n most s e c t i o n s o f t h e t r e n c h have n o t been a d j u s t e d to a l l o w f o r t h i s d e c r e a s e I n range acreage; consequently, fewer and fewer a c r e s a r e f o r c e d t o support t h e same numbers of stock. passing Thus, o v e r g r a z i n g may be more severe w i t h each year. S m a l l h i l l s o r anomalies on t h e t r e n c h f l o o r have been used as t r a d i t i o n a l w i n t e r ranges by l o c a l p o p u l a t i o n s o f mule d e e r , w h i t e - t a i l e d d e e r , Rocky Mountain b i g h o r n and elk. animals With the exception o f w h i t e - t a i l e d deer, sheep these summer a t h i g h e l e v a t i o n s i n t h e Rocky M o u n t a i n s , u s i n g v a s t areas which i n t h e f o r e s e e a b l e f u t u r e w i l l n o t be g r e a t l y m o d i f i e d by man. The c o n t i n u e d s u r v i v a l o f t h e s e p o p u l a t i o n s i s dependent upon c r i t i c a l w i n t e r and e a r l y s p r i n g ranges which d o t t h e t r e n c h f l o o r . The u t i l i z a t i o n o f t h e s e ranges c r i t i c a l f o r w i l d l i f e i n w i n t e r , by c a t t l e d u r i n g t h e summer reduces t h e f o r a g e a v a i l a b l e f o r w i l d l i f e . s In o r d e r t o o b t a i n some measure o f t h e e f f e c t s o f f o r e s t r e g e n e r a t i o n and s u c c e s s i o n on t h e s p e c i e s composition and p r o d u c t i v i t y o f t h e u n d e r s t o r y community, t h i s study was e s t a b l i s h e d under the j o i n t c o o p e r a t i o n o f t h e U n i v e r s i t y o f B r i t i s h Columbia and t h e B r i t i s h Columbia P i s h and W i l d l i f e Branch. 11 II A. METHODS AND MATERIALS Criteria for Site Selection A r e c o n n a i s s a n c e s u r v e y o f t h e Premier Ridge area and t h e s u r r o u n d i n g t r e n c h f l o o r r e v e a l e d t h a t g r a z i n g was c o n c e n t r a t e d p r i m a r i l y on s o u t h and southwestern s l o p e s and the a d j a c e n t f l a t open a r e a s o f t h e t r e n c h f l o o r . The v e g e t a t i o n o f the r i d g e appears t o be s i m i l a r t o t h e communities common t o t h e f l o o r o f t h e t r e n c h . t a t i o n o f t h e a d j a c e n t east w a l l o f t h e t r e n c h The vege(Estella Mountain) i s d i s t i n c t l y d i f f e r e n t , r e f l e c t i n g i n c r e a s e d p r e c i p i t a t i o n and c o o l e r temperatures higher elevations. associated with Aspect has a profound e f f e c t on m i c r o - c l i m a t e i n t h i s a r e a , p a r t i c u l a r l y on e f f e c t i v e s o i l m o i s t u r e ; c o n s e q u e n t l y , t h e s i t e s s e l e c t e d f o r s t u d y were r e s t r i c t e d to south and southwestern aspects. The f o r e s t c o v e r o f Premier Ridge i s composed o f ponderosa p i n e and Douglas f i r ; l o d g e p o l e p i n e and l e s s commonly l a r c h , u s u a l l y f o l l o w f i r e . ponderosa p i n e i s absent b u t western On n o r t h e a s t s l o p e s , l a r c h i s common i n moist draws. The mature montane f o r e s t stands o f a few decades ago were l a r g e l y c l e a r c u t , l e a v i n g a . s e r i e s o f secondary stands o f v a r y i n g ages and s p e c i e s c o m p o s i t i o n . Douglas f i r and ponderosa p i n e were t h e most abundant and widespread s p e c i e s , c o n s e q u e n t l y young, mature, and c l i m a x 12 stands o f t h e s e s p e c i e s were sought f o r i n t e n s i v e studyon Premier Ridge. One l o d g e p o l e s t a n d on Premier was a l s o s e l e c t e d and t h r e e open s e r a i range s i t e s were i n c l u d e d , r e p r e s e n t i n g a r e a s which were once timbered and l o g g e d , but which f a i l e d t o r e g e n e r a t e t o t r e e s . One s i t e esta- b l i s h e d by t h e B r i t i s h Columbia F o r e s t S e r v i c e , G r a z i n g D i v i s i o n , on t h e Skookumchuck P r a i r i e , a n a t u r a l g r a s s l a n d , was i n c l u d e d i n t h i s s t u d y f o r c o m p a r a t i v e F i v e s i t e s were s e l e c t e d on nearby Mountain purposes. Estella t o measure t h e e f f e c t o f i n c r e a s e d e l e v a t i o n and p r e c i p i t a t i o n on s u c c e s s i o n and p r o d u c t i v i t y . Two o f t h e s e s i t e s were logged i n t h e 1 9 5 0 ' s ; one i s a l a r c h s t a n d and the o t h e r a Douglas f i r s i t e . The r e m a i n i n g t h r e e s i t e s on E s t e l l a a r e s i t u a t e d on a 1 9 3 ^ burn w h i c h swept t h e mountain from bottom t o t o p . A l o d g e p o l e s i t e was e s t a - . b l i s h e d on an a r e a which has been dominated pine s i n c e the f i r e . by l o d g e p o l e An open f e s c u e and an open r bunchgrass s i t e were e s t a b l i s h e d on two a r e a s which have remained unforested since the f i r e . At each s i t e a 3 0 ' x 3 0 ' e x c l o s u r e , e i g h t f e e t h i g h was c o n s t r u c t e d , e x c l u d i n g a l l u n g u l a t e s from t h e plot. W i t h i n t h i s a r e a e i g h t e e n meter square quadrats were l a y e d out i n a fixed, p a t t e r n , from which t h e p r o d u c t i v i t y c l i p s were taken.. A 100 f o o t square m a c r o p l o t , c o n c e n t r i c w i t h t h e e x c l o s u r e , was l a i d out a t each s i t e . (This area 13 was n o t f e n c e d i n any way.) Trees and l a r g e shrubs were sampled from the m a c r o p l o t ; g r a s s e s , f o r b s and dwarf were sampled from the e x c l o s u r e . was completed by August May 1969. 1968. shrubs Construction of a l l exclosures Two s i t e s were added i n e a r l y These were an open b l u e g r a s s - n e e d l e g r a s s s i t e and an open b i t t e r b r u s h s i t e , b o t h l o c a t e d on P r e m i e r R i d g e . In two c a s e s , the open bluebunch wheatgrass s i t e : on P r e m i e r Ridge and t h e open f e s c u e s i t e on E s t e l l a , the e n t i r e m a c r o p l o t was fenced. B. Techniques Site Description The a s p e c t and p e r c e n t s l o p e o f each p l o t was • r e c o r d e d i n t h e f o l l o w i n g manner. The p e r c e n t s l o p e was o b t a i n e d w i t h a Suunto L e v e l by s i g h t i n g from t h e c e n t r e o f t h e upper m a c r o p l o t boundary m a c r o p l o t boundary. slope d i r e c t l y . ) t o the c e n t r e o f t h e lower (The i n s t r u m e n t s c a l e reads p e r c e n t The a s p e c t was measured by compass, con- s i d e r i n g the m a c r o p l o t as a p l a n e s u r f a c e ; the d i r e c t i o n , i n degrees from magnetic n o r t h , i n w h i c h the p l a n e was t i l t e d was c o n s i d e r e d t o be the a s p e c t . A map was drawn f o r each m a c r o p l o t showing the l o c a t i o n o f each t r e e , stump and l a r g e s h r u b , i n c l u d i n g a r e f e r e n c e number under which the v a r i o u s parameters c r i b i n g t h a t p l a n t were l i s t e d . A canopy map des- of t h e f o r e s t o v e r s t o r y was made f o r the m a c r o p l o t u s i n g a 3 meter square 14 g r i d of 100 p o i n t s . At each p o i n t on t h e g r i d a. v e r t i c a l s i g h t i n g was taken w i t h a G i m b a l l s i g h t (Dodd l i v i n g branches, "hits". 1969). Only- t r u n k s and l i m b s were r e c o r d e d as canopy Open sky o r dead branches were r e c o r d e d as m i s s e s . For each s i g h t i n g t h e h i t o r miss was r e c o r d e d f o r a. s m a l l dot on t h e m i r r o r o f t h e i n s t r u m e n t . S i n c e t h e g r i d has 100 p o i n t s , t h e number o f h i t s r e c o r d e d i s t h e p e r c e n t f o r e s t canopy c o v e r , a t eye l e v e l ( 5 ) - T h i s method s h o u l d 1 not be confused w i t h a s i m i l a r method which r e c o r d s t h e canopy cover o f each t r e e on an i n d i v i d u a l b a s i s . Since canopies o v e r l a p , v a l u e s above 1 0 0 $ a r e common, but t h i s study c o n s i d e r e d t h e canopy as a u n i t , and u s i n g t h i s system, v a l u e s h i g h e r than 80$> a r e uncommon. Each t r e e mapped i n t h e m a c r o p l o t was c l a s s i f i e d by s p e c i e s , age, d i a m e t e r b r e a s t h e i g h t (DBH), d i a m e t e r a t stump h e i g h t (DIH) and t o t a l h e i g h t . The l o c a t i o n , age a t c u t t i n g t i m e , s p e c i e s and c o n d i t i o n o f a l l stumps i n t h e macroplot was r e c o r d e d . S o a p o l a l l i e ( S h e r p h e r d i a canadensis ) p l a n t s i n each macroplot were mapped and ranked a c c o r d i n g t o t h e i r f o l i a r diameter and h e i g h t . Bitterbrush ( P u r s h i a t r i d e n t a t a . ) p l a n t proved t o be t o o numerous t o measure i n d i v i d u a l l y ; t h e r e f o r e a. 10 rank s c a l e o f s i z e was used t o r e c o r d t h i s s p e c i e s i n the macroplot. 15 The u n d e r s t o r y v e g e t a t i o n (dwarf shrubs, forbs and g r a s s e s ) a t each s i t e was d e s c r i b e d u s i n g Daubenmire's l/10th meter frame method (Daubenmire, were counted i n each m a c r o p l o t , 1959). F o r t y frames 20 on each s i d e o f t h e ex- c l o s u r e , p a r a l l e l i n g the contour. C. Determination of Characteristic Stand Age The assessment o f age o f a stand o f t r e e s o r an open s e r a i community i s n o t a s i m p l e procedure. While the t r e e s a t a p a r t i c u l a r s i t e may be, i n t h e main, 50 o l d , t h e d i s t u r b a n c e which l e d t o t h e e s t a b l i s h m e n t years o f the s t a n d i n t h e f i r s t p l a c e , may have o c c u r r e d many y e a r s previously. F o r example, open s e r a i communities on t h e southwest s i d e o f Premier Ridge a r e t h e r e s u l t o f l o g g i n g which o c c u r r e d about 1910, erated t o f o r e s t . b u t they have n o t y e t regen- Thus, w h i l e t h e i r s u c c e s s i o n a l age i s about 60 y e a r s , t h e i r age i n terms o f f o r e s t succession i s zero. The terms s u c c e s s i o n a l age, c h a r a c t e r i s t i c age and premodal age, a r e used I n t e r c h a n g e a b l y stand- i n this text, and r e f e r t o t h e e a r l i e s t p o i n t o f I n f l e c t i o n o f t h e peak on a g r a p h , w h i c h r e p r e s e n t s t h e m a j o r i t y o f t h e t r e e s I n the s t a n d . The u s e o f a premodal age p e r m i t s t o be made from t h e time a major e n v i r o n m e n t a l occurred. predictions; disturbance F i g u r e 3 shows a graph o f t h e t r e e s found i n one F i g u r e 3- 1969 I l l u s t r a t i o n of the d e t e r m i n a t i o n of c h a r a c t e r i s t i c stand age. The t r e e s are grouped i n t o age c l a s s e s (each c o n t a i n i n g 5 year c l a s s e s ) and p l o t t e d on a graph. The p o i n t of i n f l e c t i o n of that peak which represents tne D u l k of the t r e e s i s taken as the date at which the stand was i n i t i a t e d . The c h a r a c t e r i s t i c stand age of t h i s example i s 6 5 y e a r s . Age Class 1904 17 m a c r o p l o t , i l l u s t r a t i n g the d e t e r m i n a t i o n o f c h a r a c t e r istic The t r e e s were grouped I n t o 5 y e a r s t a n d age. v a l s or c l a s s e s and p l o t t e d a g a i n s t t i m e . inter- Most o f the t r e e s a r e r e p r e s e n t e d by a l a r g e peak, and the e a r l i e s t p o i n t o f i n f l e c t i o n of t h i s peak i s t h e " c h a r a c t e r i s t i c age" o f t h e site. D. Annual P r o d u c t i v i t y Assessments (Net p r o d u c t i v i t y o f B l i s s and Westlake) To f a c i l i t a t e p r o d u c t i v i t y assessments, v e g e t a t i o n a t each s i t e was the divided into s i x categories; ( l ) t r e e s , ( 2 ) l a r g e s h r u b s , ( 3 ) dwarf s h r u b s , (4) forbs, (5) grasses, (6) bearberry. (l) Trees The a n n u a l p r o d u c t i v i t y o f the t r e e s was derived i n crude terms by c a l c u l a t i n g t h e s t a n d i n g volume o f t i m b e r i n each m a c r o p l o t i s t i c stand and d i v i d i n g t h i s f i g u r e by t h e c h a r a c t e r - age. The volume o f each t r e e was c a l c u l a t e d u s i n g the f o r m u l a (Smith and Breadon- 1 9 6 4 ) 1. V = a + bH B where V a b B H = = = = = The volume increment per y e a r was volume i n f t . 3 species coefficent 1 b a s a l a r e a at- DBH height of t r e e calculated using the f o r m u l a 2. p s jr ]/ ~T~* where *P = i n c r e m e n t / y e a r A = c h a r a c t e r i s t i c stand age 18 (2) B i t t e r b r u s h and S o a p o i a l l i e The a n n u a l p r o d u c t i v i t y o f b i t t e r b r u s h and s o a p o i a l l i e was determined by subsampling representative p l a n t s which had been p r e v i o u s l y mapped i n t h e m a c r o p l o t and a s s i g n e d a s i z e c a t e g o r y . by Q u a d v l e i g A s i m i l a r method was used (1968). Two r e p r e s e n t a t i v e s i z e s o a p o i a l l i e p l a n t s were s e l e c t e d a t random (from a l i s t ranked a c c o r d i n g t o s i z e ) and c u t down a t ground level. The c u r r e n t y e a r ' s t w i g s and a l l t h e l e a v e s on t h e p l a n t were removed and s t o r e d In paper bags. The r e m a i n i n g p o r t i o n o f t h e p l a n t (wood o l d e r than 1 y r . ) was a i r - d r i e d on t h e open range f o r 2 weeks. A t t h i s t i m e , t h e p l a n t was weighed and a s e c t i o n was c u t from t h e base t o age t h e p l a n t . These s e c t i o n s were sanded smooth and examined under a low power m i c r o s c o p e ; l i g h t o i l was used t o f a c i l i t a t e t h e c o u n t i n g o f a n n u a l rings.. To d e t e r m i n e t h e s i z e o f each p l a n t , t h e f o l l o w i n g f o r m u l a was used Crude Volume = 3.l4 x r 2 x h where r = r a d i u s o f p l a n t a.t ground l e v e l h = t o t a l height of plant The crude volume f o r a l l t h e s o a p o i a l l i e p l a n t s i n each m a c r o p l o t was d e t e r m i n e d . The a n n u a l p r o d u c t i v i t y (annual t w i g s p l u s a l l l e a v e s on t h e p l a n t ) was determined 19 by o v e n - d r y i n g t h e c u r r e n t t w i g s and l e a v e s a t 50° C t o constant weight. F o r each p l a n t , and f o r each s i t e , an i n d e x o f t h e weight o f t w i g s and l e a v e s produced a n n u a l l y p e r c u b i c f o o t ( o f crude volume) was c a l c u l a t e d . The t o t a l crude volume m u l t i p l i e d by t h e average weight o f a n n u a l twigs and l e a v e s y i e l d e d a t o t a l a n n u a l p r o d u c t i v i t y for s o a p o i a l l i e at that s i t e . figure A l l p l a n t s were sampled i n August 1 9 6 9 when t w i g e l o n g a t i o n had ceased. The b i t t e r b r u s h p l a n t s i n t h e m a c r o p l o t s proved t o be t o o numerous t o c o u n t , hence a s i z e c l a s s system was adopted, employing a 10 rank s c a l e . R e p r e s e n t a t i v e , randomly s e l e c t e d p l a n t s i n each m a c r o p l o t were c u t a t ground level and t h e i r c u r r e n t t w i g s and a t t a c h e d l e a v e s were removed. The l e a v e s on t h e r e m a i n i n g p o r t i o n o f t h e - p l a n t (secondary wood) were n o t c o l l e c t e d . The p l a n t s were then d r i e d on t h e open range f o r two weeks. At t h e end o f t h i s p e r i o d t h e o l d wood was weighed and a s e c t i o n was removed from t h e base o f the p l a n t f o r a g i n g . The t o t a l m a c r o p l o t p r o d u c t i v i t y o f b i t t e r b r u s h was determined by m u l t i p l y i n g t h e average a n n u a l weight o f oven d r i e d t w i g s and l e a v e s f o r each s i z e c l a s s by t h e number o f plants i n that s i z e c l a s s . I n summary, t h e s e t o t a l s a t o t a l weight f o r t h a t s i t e . sampled produced A l l b i t t e r b r u s h p l a n t s were i n August when a n n u a l t w i g growth had ceased. B i t t e r b r u s h and s o a p o i a l l i e were not sampled from 20 w i t h i n t h e e x c l o s u r e ; s i z e removal o f such l a r g e components of t h e v e g e t a t i o n c o u l d s e v e r e l y a l t e r any changes i n the community a f f o r d e d hy t h e i r p r o t e c t i o n from g r a z i n g . (3) G r a s s e s , f o r b s and dwarf shrubs The g r a s s e s , f o r b s and.dwarf shrubs were c l i p p e d from one meter q u a d r a t s w h i c h l a y w i t h i n t h e e x c l o s u r e fence. 1968 The q u a d r a t s were p r e - c l i p p e d i n t h e l a t e f a l l o f and were c l i p p e d t h r e e t i m e s d u r i n g 1 9 6 9 ; t h e s e c l i p p i n g p e r i o d s were June 2 - 7 , J u l y 23 - 27 and October 4 - 9 . June c l i p o c c u r r e d d u r i n g t h e growing season, t h e J u l y The clip f o l l o w e d mid-summer dormancy o f t h e g r a s s e s , and t h e October c l i p preceded permanent w i n t e r snows. At each c l i p p i n g d a t e , 6 meter q u a d r a t s were c l i p p e d a t each s i t e ; t h e t h r e e com- ponents o f t h e v e g e t a t i o n were c o l l e c t e d i n s e p a r a t e bags. These samples were a i r - d r i e d i n t h e f i e l d and t h e n o v e n - d r i e d in a forced-air drier at 5 0 ° C u n t i l c o n s t a n t weight was achieved. Unless otherwise noted, the y i e l d f i g u r e s represent the J u l y c l i p when t h e y p e r t a i n t o g r a s s , f o r b o r dwarf shrub material. (4) Bearberry Bearberry or k i n n i k i n n i k (Arctostaphylos u v a - u r s i ) was sampled on 4 t o 6 one-meter square q u a d r a t s o u t s i d e t h e e x c l o s u r e i n t h e month o f August. A l l the bearberry i n the 21 quadrat was removed; when a runner c r o s s e d t h e quadrat frame i t was c u t a t t h a t p o i n t . from o l d e r growth. to a constant New growth was separated These samples were o v e n - d r i e d a t 5 0 ° C weight. The f l o r i s t i c and p r o d u c t i v i t y d a t a have been p r e s e n t e d i n g r a p h i c form i n t h i s t e x t . The c u r v e s on t h e s e graphs a r e r e p r e s e n t a t i v e o f the t r e n d o f t h e d a t a , and s h o u l d n o t be i n t e r p r e t e d as a l e a s t squares fit. 22 I I I OBSERVATIONS AND RESULTS A. Site Description S i x t e e n non-randomly l o c a t e d s i t e s were s e l e c t e d f o r i n t e n s i v e study. These i n c l u d e d one n a t u r a l grassland, n i n e f o r e s t e d a r e a s and f i v e a r e a s which once were f o r e s t e d hut which have f a i l e d t o r e g e n e r a t e f o l l o w i n g l o g g i n g and/or burning. Most o f t h e s i t e s ( t e n ) were l o c a t e d on P r e m i e r Ridge on communities used by w i l d and domestic u n g u l a t e s . The t h r e e open s i t e s ( u n f o r e s t e d ) on P r e m i e r Ridge i n - c l u d e d a r e a s l i g h t l y , m o d e r a t e l y and h e a v i l y used by domestic cattle. H i s t o r i c a l l y , t h e s e s i t e s compare t o t h e r e s t o f the s i t e s on P r e m i e r . Generally t h e s i t e s a r e named a f t e r a c o n s p i c u o u s element o f t h e i r v e g e t a t i o n o r by t h e i r l o c a t i o n . Timbered s i t e s u s u a l l y b e a r t h e name and some rough i n d i c a t i o n of the maturity o f t h e i r dominant t r e e s p e c i e s . Open s e r a i s i t e s ( b e i n g t r e e l e s s ) a r e named a f t e r a shrub o r g r a s s species. The s i t e s a r e n o t d i r e c t l y comparable t o t h o s e on Premier Ridge because t h e y r e f l e c t t h e e f f e c t o f e l e v a t i o n . S i n c e w i l d u n g u l a t e s may f o r a g e on t h e east w a l l o f t h e t r e n c h below 6,000 f t . i n mild winters and d u r i n g e a r l y f a l l , a knowledge o f t h e s p e c i e s l a t e s p r i n g and c o m p o s i t i o n and p r o - d u c t i v i t y o f t h e s e a r e a s , e s p e c i a l l y f o l l o w i n g f i r e s and logging, i s pertinent. 23 1. Skookumchuck P r a i r i e N a t u r a l G r a s s l a n d T h i s s i t e I s the o n l y n a t u r a l g r a s s l a n d p l o t In the s e r i e s . I t I s r e p r e s e n t a t i v e o f the l i m i t e d and s c a t t e r e d acreage o f n a t u r a l g r a s s l a n d s which dot the f l o o r of the Rocky Mountain Trench. used h e a v i l y by domestic v e g e t a t i o n remains. These g r a s s l a n d s have "been s t o c k and v e r y l i t t l e o f the p r i s t i n e The d a t a used i n t h i s s t u d y were d e r i v e d from an e x c l o s u r e b u i l t i n 1952 on t h e Skookumchuck P r a i r i e by the B r i t i s h Columbia F o r e s t S e r v i c e . t a t i o n has responded w e l l t o t h e 17 g r a z i n g and i s now The n a t u r a l vege- y e a r s o f p r o t e c t i o n from f a i r l y r e p r e s e n t a t i v e o f the c l i m a x g r a s s - lands o f the a r e a . The community dominants a r e wheatgrass and rough f e s c u e which occupy 63% cover, r e s p e c t i v e l y . Junegrass 8% o f the ground s u r f a c e . bluebunch and 9% o f t h e ( K o e l e r i a c r i s t a t a ) covers B l u e g r a s s (Poa spp. ) and needle- g r a s s ( S t i p a spp.) were dominants on the s i t e p r i o r t o the c o n s t r u c t i o n of the e x c l o s u r e . Both genera have been a l l but e l i m i n a t e d from the e x c l o s u r e . No shrubs o r t r e e s a r e p r e s e n t but ponderosa p i n e o c c u r s nearby on the g r a v e l l y , v e r y porous s o i l which c h a r a c t e r i z e s the Skookumchuck Prairie. The t o t a l ground c o v e r by g r a s s e s was o c c u p i e d a t o t a l cover of 6%, the p r i n c i p a l . f o r b {3%) 80$. Forbs p h l o x ( P h l o x ca e s p i t o s a ) was but n i n e o t h e r s p e c i e s were r e c o r d e d . An u n p r o t e c t e d a r e a a d j a c e n t t o but o u t s i d e the 24 F i g u r e 4. The Skookumchuck P r a i r i e , a n a t u r a l g r a s s l a n d . 25 e x c l o s u r e f e n c e was a l s o sampled. Junegrass was abundant s p e c i e s o c c u p y i n g a c o v e r o f 16$. b l u e g r a s s o c c u p i e d 12% and 3% r e s p e c t i v e l y . nant bluebunch wheatgrass p r e s e n t i n t r a c e amounts. o u t s i d e the p l o t was k0%. c o v e r was t h e most Needlegrass and The once domi- 10% and rough f e s c u e The t o t a l ground was c o v e r by g r a s s e s Forbs were common, e l e v e n s p e c i e s being recorded, pussytoes ( A n t e n n a r i a p a r i i f l o r a ) and flea- bane ( E r i g e r o n l i n e a r i s ) were the most abundant s p e c i e s h a v i n g ground c o v e r s o f 2% and 3% r e s p e c t i v e l y . Skookumchuck P r a i r i e p l o t i s shown I n F i g u r e 2. Premier Ridge N o n - f o r e s t e d The 4. Sites Mature c l i m a x montane f o r e s t p r e v i o u s l y o c c u p i e d the t h r e e n o n - f o r e s t e d s i t e s on Premier Ridge. was Douglas f i r t h e p r i n c i p a l s p e c i e s and stumps of t h i s s p e c i e s w i t h b a r k a t t a c h e d , remained decay. i n t h e a r e a , i n v a r i o u s s t a g e s of The removal o f the f o r e s t and t h e t r e e canopy has g i v e n r i s e t o widespread open, s e r a i , n o n - f o r e s t e d P r e v i o u s l y more w i d e s p r e a d , t h e s e communities communities. are l a r g e l y now c o n f i n e d t o the south and southwestern s l o p e s o f Premier Ridge. a- Bluegrass-Needlegrass Site This s i t e i s subjected to the heaviest g r a z i n g p r e s s u r e (by domestic s t o c k ) o f a l l the s i t e s on Ridge. Premier A d j a c e n t t o A l k a l i Lake, one o f the main water sources f o r domestic by c a t t l e from May s t o c k , t h i s community i s h e a v i l y grazed 1 t o the l a t e f a l l . Kentucky bluegrass F i g u r e 5. The b l u e g r a s s - n e e d l e g r a s s p l o t , l o c a t e d n e a r A l k a l i Lake. N o t e t h e stumps o f t h e p r e v i o u s f o r e s t and t h e "weedy" i n d i c a t o r s p e c i e s o f overgrazing i n the foreground. Figure 6. The b l u e g r a s s - n e e d l e g r a s s e x c l o s u r e . reduced c a r r y o v e r o u t s i d e the f e n c e . Notice the 28 (Poa p r a t e n s l s ) and Canada b l u e g r a s s (Poa compressa) were abundant a t t h i s s i t e , f o r m i n g a t o t a l o f 2 2 $ o f t h e herbaceous c o v e r . Junegrass and downy brome (Bromus tectorum) were a l s o common c o v e r i n g 1 1 $ and 8 $ o f t h e ground s u r f a c e respectively. Bluebunch wheatgrass ( c o v e r 2 $ ) and n e e d l e - g r a s s ( c o v e r 3 $ ) were p r e s e n t i n l e s s e r q u a n t i t i e s . teen s p e c i e s o f f o r b s were r e c o r d e d a t t h i s ,sit.e. a c h i e v e d a ground c o v e r g r e a t e r than 2 $ . SevenNo s p e c i e s Shrubs were p r e v a - l e n t , b i t t e r b r u s h b e i n g t h e most abundant w i t h a ground c o y e r of 1 7 $ . Saskatoon ( A m e l a n c h i e r a l n l f o l l a ) covered 4 $ w h i l e f l a t - t o p s p i r a e a ( S p i r a e a l u c i d a ) covered 2 $ . Bearberry was abundant, c o v e r i n g 1 2 $ o f t h e ground s u r f a c e . b. Bitterbrush Site . ; : T h i s a r e a i s t h e second open s i t e s . i n the s e r i e s of unforested Located about 3 / 8 mi., from A l k a l i Lake, i t r e - c e i v e s moderate t o heavy g r a z i n g p r e s s u r e from cattle. Kentucky b l u e g r a s s and Canada b l u e g r a s s a r e t h e most abundant grasses, both species a c h i e v i n g a cover o f 1 7 $ . was a l s o common, c o v e r i n g l 4 $ . Downy brome Junegrass was l e s s common, c o v e r i n g 2 $ , w h i l e b l u e b r u n c h wheatgrass and n e e d l e g r a s s were p r e s e n t i n t r a c e amounts ( c o v e r l e s s than 1 $ ) . Twenty-two s p e c i e s o f f o r b s were r e c o r d e d . r o o t ( B a l s a m o r h l z a s a g i t t a t a ) covered Balsam 1 0 $ , Oyster p l a n t (Tragopogon d u b i u s ) covered 1 $ , showy a s t e r ( A s t e r c o n s p l c u u s 29 F i g u r e 7. The b i t t e r b r u s h s i t e . i n t h e background. The e x c l o s u r e can be seen Figure 8. A c l o s e u p of the bitterbrush exclosure. 31 covered 4 $ . The t o t a l c o v e r by f o r b s a t t h i s s i t e was 3 4 $ . Shrubs were v e r y abundant, b i t t e r b r u s h dominated w i t h a ground the s i t e c o v e r o f 2 5 $ , saskatoon covered 2 $ , w h i l e s p i r a e a covered 2 $ . B e a r b e r r y was p r e s e n t i n t r a c e amounts. c. The R e l i c t Bluebunch Wheatgrass S i t e T h i s s i t e i s t h e t h i r d i n t h e open u n f o r e s t e d series. S i t u a t e d on a s t e e p s l o p e about two m i l e s from the n e a r e s t water s o u r c e , t h i s a r e a r e c e i v e s a l m o s t no g r a z i n g from domestic s t o c k . I t I s w e l l used by w i n t e r i n g b i g h o r n sheep and mule d e e r . Use by e l k i s l i g h t . Bluebunch wheatgrass 5 1 $ o f t h e ground surface. dominates t h e s i t e , c o v e r i n g Junegrass i s a l s o common, c o v e r i n g 9 $ , a t r a c e o f downy brome was r e c o r d e d . cover by g r a s s s p e c i e s was 6 0 $ . Total The most abundant f o r b was balsam r o o t w i t h a c o v e r o f 3 $ . Pour o t h e r f o r b s were r e corded i n t r a c e amounts. T o t a l c o v e r by f o r b s was 4 $ . Shrubs were n o t abundant a t t h i s s i t e . 4$, Bitterbrush covered s a s k a t o o n o c c u p i e d 2 $ and r o s e (Rosa spp. ) covered 3 $ . T o t a l c o v e r by shrubs was 9 $ . 3. Premier Ridge F o r e s t e d S i t e a. The Young Douglas F i r S i t e T h i s p l o t i s s i t u a t e d i n a stand o f mature t i m b e r which was s e l e c t i v e l y logged about 1 9 1 0 . Some t r e e s were cut. i n r e c e n t y e a r s . The stand p r e s e n t l y i s composed l a r g e l y o f young f i r t r e e s from 3 t o 15 f t . i n h e i g h t , h u t 32 F i g u r e 9'. The r e l i c t bluebunch-wheatgrass s i t e . Steepness of s l o p e has a l l o w e d t h e s e r i d g e s t o escape the heavy g r a z i n g which i s c h a r a c t e r i s t i c o f t h e lower a r e a s i n t h i s photograph. 33 a few mature t r e e s remain on t h e s i t e . While the area I s probably not r e p r e s e n t a t i v e of a c l e a r - c u t logging p r a c t i c e , no s i t e s were found which c o n t a i n e d v e r y young f i r s t a n d s . Most o f t h e mature Douglas f i r was removed from t h e r i d g e e a r l y i n t h e t w e n t i e t h c e n t u r y and r e g e n e r a t i o n e i t h e r commenced i m m e d i a t e l y o r has been " s t a l l e d " by c l i m a t i c and g r a z i n g f a c t o r s . The young f i r s t a n d c o n t a i n e d 1 9 3 0 stems p e r a c r e and had a f o r e s t canopy c o v e r o f 2 0 $ . 22 y e a r s . The pre-modal age was A few l a r c h and l o d g e p o l e p i n e were p r e s e n t a t t h i s s i t e , b u t ponderosa p i n e was absent. The g r a s s component o f the u n d e r s t o r y was l a r g e l y composed o f p i n e g r a s s ( C a l a m a g r o s t l s rub esc ens) which had a ground c o v e r o f 4 2 $ . Rough fescue, was a l s o abundant a t 1 1 $ and j u n e g r a s s covered o n l y 1 , 2 $ . The t o t a l c o v e r by g r a s s s p e c i e s was 5 4 $ . F i f t e e n species o f f o r b s were r e c o r d e d , t h e most abundant b e i n g w i l d b e r r y ( F r a g a r i a g l a u c a ) and w h i t e p u s s y t o e s . by f o r b s was 1 5 $ . straw- The t o t a l cover- Shrubs were common, s a s k a t o o n covered 7 $ , s p i r a e a 4 $ , b i t t e r b r u s h , s o a p a l a l l i e and r o s e t o g e t h e r covered 1 $ . B e a r b e r r y was v e r y common, o c c u p y i n g 1 7 $ and making up one h a l f o f t h e t o t a l shrub cover o f 33$. b. The Middle-aged Douglas F i r S i t e T h i s s i t e had a. f o r e s t canopy c o v e r o f 5 6 $ and a pre-modal age o f 5 5 y e a r s . However, l o g g i n g d u r i n g t h e summer o f 1969 removed s e v e r a l mature t r e e s from t h i s s i t e . T h i s had F i g u r e 10. Figure 11. R e g e n e r a t i o n on t h e steep western a s p e c t s has been slow. T h i s s i t e was cut about 1 9 1 5 - The " t e r r a c e " a r e a . o f Premier R i d g e . Note the r a p i d , widespread r e g e n e r a t i o n o f young trees. Figure 1 2 . The young Douglas f i r site. 36 l i t t l e e f f e c t on t h e y i e l d s r e c o r d e d d u r i n g t h i s study. There were 6 0 5 stems p e r a c r e a t t h e s i t e , most o f which were Douglas f i r , h u t one l a r c h and s e v e r a l ponderosa p i n e t r e e s were a l s o p r e s e n t . P i n e g r a s s dominated t h e s p a r s e u n d e r s t o r y community p r e s e n t a t t h i s s i t e , w i t h a ground cover o f 2 9 $ . Bluebunch wheatgrass, j u n e g r a s s and needlegra.ss were p r e s e n t I n v e r y s m a l l q u a n t i t i e s . b l u e g r a s s s p e c i e s were p r e s e n t . by g r a s s e s was 46$. The t o t a l ground No cbver F i f t e e n s p e c i e s o f f o r b s were r e - c o r d e d , b u t they t o t a l l e d o n l y 1 7 $ ground c o v e r . Penstemon (Penstemon s p p . ) , w i l d s t r a w b e r r y , t i m b e r m i l k v e t c h ( A s t r a g a l u s m i s e r v a r . s e r o t i n u s ) and yarrow m i l l e f o l i u m ) were t h e most common. (Achillea The r a p i d l y developing f o r e s t canopy was p r o b a b l y r e s p o n s i b l e f o r t h e dead and t h i n l y developed shrubs a t t h i s s i t e . B i t t e r b r u s h covered o n l y 3 $ , s p i r a e a 5 $ , s a s k a t o o n 7 $ and b e a r b e r r y 2 $ . Total shrub cover was 1 8 $ . c. The Mature Douglas F i r S i t e T h i s was t h e o n l y p l o t which was n o t e s t a b l i s h e d on a south o r southwest s l o p e . The o n l y r e m a i n i n g stand o f mature Douglas f i r on Premier Ridge i s l o c a t e d on t h e n o r t h east s l o p e o f t h e r i d g e . Since t h i s aspect i s d i s t i n c t l y more humid than those on which t h e o t h e r p l o t s were l o c a t e d , r i g i d d i r e c t comparisons between them should not be made. Figure 13. The middle-aged Douglas f i r s i t e . N o t i c e t h e dead shrubs i n the f o r e g r o u n d . Figure 14. The mature Douglas f i r site. 39 The a r e a s e l e c t e d f o r s t u d y has a pre-modal age o f 95 years, and 331 73$. stems per a c r e , w i t h a f o r e s t canopy c o v e r o f The o n l y g r a s s p r e s e n t was p i n e g r a s s which had a ground c o v e r o f 43$. amounts. S i x s p e c i e s o f f o r b s were p r e s e n t i n t r a c e S p i r a e a was of the ground, Oregon grape (Mahonia r e p e n s ) and r o s e were p r e s e n t i n t r a c e amounts. surface. 26$ t h e most abundant shrub c o v e r i n g Moss covered 12$ o f the ground Scattered s o a p o i a l l i e p l a n t s occurred throughout the s i t e , u s u a l l y h o l e s i n t h e f o r e s t canopy, d. Young Ponderosa P i n e S i t e . This s i t e i s r e p r e s e n t a t i v e of those stands of t r e e s w h i c h have a r i s e n as a r e s u l t o f t h e l o g g i n g and T h i s stand had 958 which removed the mature t i m b e r . p e r a c r e and a f o r e s t canopy c o v e r o f 49$. age was 80 years. 1 The fires stems pre-modal While, t h e s t a n d has more f i r . t r e e s than p i n e , the p i n e s c u r r e n t l y dominate the f i r . The undercover was. s p a r s e , w i t h p i n e g r a s s as t h e most abundant s p e c i e s c o v e r i n g 29$. Rough f e s c u e c o v e r e d 5$ and j u n e g r a s s 1$ o f the ground s u r f a c e . The t o t a l cover by g r a s s was 35$. S i x t e e n s p e c i e s o f f o r b s covered a t o t a l o f 10$ o f the ground s u r f a c e . Nodding o n i o n ( A l l i u m cernuum), w i l d straw- b e r r y , balsam r o o t and yarrow were a l l p r e s e n t , c o v e r i n g about 1$ o f t h e ground. t o t a l c o v e r was and s p i r a e a 1$. 12$. Shrubs were not abundant, t h e i r Saskatoon covered 4$, B e a r b e r r y covered 2$. bitterbmsh 4$ 40 e. Middle-aged Thig near no Alkali site Lake. Is situated p r e - m o d a l age 49$. cover, was was the the 2 $ and also 4$ the bluebunch canopy, Pinegrass covering 22$. The total ("17$), w h i l e a c o v e r was saskatoon 32$, covered half 11$ of were total most a b u n d a n t c o v e r i n g t h e p l a n t s -were t h i n and shrub Rough covers T h i r t e e n species of forbs covered Shrubs, were common, b u t bearberry forest are forest. T r a c e amounts o f j u n e g r a s s T i m b e r m i l k v e t c h was developed. earlier wheatgrass are present with respectively. knoll There T h e r e were 2 6 1 stems p e r a c r e . recorded. of 23$. stand. e x i s t e n c e o f an 1 0 0 y e a r s , and was Site top o f a d r y t h e most a b u n d a n t u n d e r s t o r y g r a s s f e s c u e and 4$ on Pine It i s a very uniform stumps s u g g e s t i n g The Ponderosa 14$. weakly of this and being bitterbrush ? f. Climax A 280 year Ponderosa Pine o l d stand to represent the climax site had a c r e , and major a forest appears forest canopy c o v e r Site o f p o n d e r o s a p i n e was chosen of the t r e n c h f l o o r . This o f 38$ w i t h 74 per t o have been r e l a t i v e l y u n a f f e c t e d by env i r o nm en t a 1 disturbances i n recent p r i n c i p a l understory g r a s s was june- 1$ and the total 5$. 21$ o f the s u r f a c e . Rough f e s c u e c o v e r e d 36$. T h i r t e e n species of forbs Balsam r o o t a t 12$, of and grass and timber . The 11$ Bluebunch wheatgrass covered c o v e r by g r a s s was times. p i n e g r a s s c o v e r i n g 18$ the s u r f a c e . covered stems covered milk Figure 15. The young ponderosa p i n e site. 42 v e t c h a t 4 $ were t h e most prominent species. Shrubs were abundant under t h e r e l a t i v e l y open canopy o f t h e c l i m a x f o r e s t , covering a t o t a l of 35$- K i n n i k i n n i k covered 1 7 $ , b i t t e r b r u s h 1 5 $ , s a s k a t o o n 4 $ and s p i r a e a c o v e r e d 1 $ . g. The Lodgepole P i n e Stand The l o d g e p o l e p i n e stand on Premier Ridge i s r e p r e s e n t a t i v e o f r e l a t i v e l y 'uniform stands which on t h e s t u d y a r e a . - occur These stands a r e t h e r e s u l t o f f i r e s which f o l l o w e d l o g g i n g . The l o d g e p o l e s i t e on Premier i s l o c a t e d on a burn w i t h i n t h e c l i m a x ponderosa pine f o r e s t . S c a t t e r e d t r e e s from t h e o r i g i n a l f o r e s t s t i l l remain. The dense l o d g e p o l e s i t e had a canopy c o v e r o f 7 8 $ and a p r e modal age o f 65 years. There were 3,459 stems p e r a c r e . P i n e g r a s s was t h e main u n d e r s t o r y g r a s s w i t h a canopy cover o f 3 9 $ . Rough f e s c u e had a c o v e r o f 2 $ . s p e c i e s o f f o r b s covered 1 5 $ . berry.were Fifteen Pussytoes and w i l d straws t h e most common c o v e r i n g , 2 $ and 1$ r e s p e c t i v e l y . The shrub c o v e r was 2 0 $ i n t o t a l , b u t appeared t o be de- c l i n i n g as s p a r s e o r dead p l a n t s were common. Kinnikinnik was abundant, c o v e r i n g 1 0 $ , s a s k a t o o n covered 7 $ and b i t t e r - brush 2 $ . 4. The E s t e l l a Mountain F o r e s t e d . S i t e s The "Regenerating D o u g l a s . f i r " and t h e " L a r c h " s i t e s on E s t e l l a Mountain were s e l e c t i v e l y logged about 1952. These s i t e s a r e r e p r e s e n t a t i v e o f t h e t y p e s o f l o g g i n g used i n t h e a r e a and i t s subsequent e f f e c t s on t h e u n d e r s t o r y 43 community. The r e m a i n i n g t h r e e s i t e s , the s e r a i bluebunch wheatgrass, the s e r a i f e s c u e and the l o d g e p o l e a r e a , were e s t a b l i s h e d on a b u r n which o c c u r r e d i n 193^- The s e r a i s i t e s have f a i l e d t o r e g e n e r a t e t o t r e e s . two The lodge- p o l e s i t e i s r e p r e s e n t a t i v e o f the r e f o r e s t e d a r e a which developed f o l l o w i n g the f i r e i n the o r i g i n a l stands w h i c h were Douglas f i r and w h i t e b a r k p i n e ( P l n u s a l b i c a u l i s ) . Ponderosa p i n e i s n e a r l y absent (above 4,000 from t h e w a l l s o f the t r e n c h f t . ) , Douglas f i r i s p r e v a l e n t , as i s l a r c h , : . and on the n o r t h and n o r t h e a s t s l o p e s Englemann spruce i s v e r y common. a. The R e g e n e r a t i n g Douglas F i r S i t e The r e g e n e r a t i n g Douglas f i r s i t e a t the 4 , 1 7 0 f t . e l e v a t i o n was t h i n n e d by s e l e c t i v e l o g g i n g about 1952. S i t u a t e d on a bench w i t h g r a v e l l y , w e l l - d r a i n e d s o i l , s i t e has a pre-modal age o f 17 y e a r s . this However, o l d mature t r e e s remain a t the s i t e and comprise most o f the p r e s e n t day f o r e s t canopy cover o f 3 5 $ . Stands which have been s e l e c t i v e l y logged a r e u s u a l l y d i f f i c u l t t o age. Con- s e q u e n t l y , the age has been d e r i v e d from the time o f the l a s t major e n v i r o n m e n t a l d i s t u r b a n c e ( l o g g i n g , i n t h i s case). There i s no evidence t o suggest has been burned i n r e c e n t t i m e s . The 553 stems per a c r e and p i n e g r a s s was that t h i s stand stand d e n s i t y was the most abundant u n d e r s t o r y g r a s s c o v e r i n g 4 2 $ o f the ground s u r f a c e . Rough Figure 1 7 . A c l o s e - u p o f t h e middle-aged ponderosa p i n e site. F i g u r e ].8. E s t e l l a M o u n t a i n a s s e e n f r o m ttee f l o o r the Rocky M o u n t a i n T r e n c h . of Figure 19. The l o d g e p o l e p i n e s i t e on Premier Ridge. Note the o l d ponderosa p i n e " v e t e r a n s " which s u r v i v e d the f i r e which gave r i s e t o the l o d g e p o l e stand In the background. 47 f e s c u e was p r e s e n t i n t r a c e amounts, p o s s i b l y r e i n v a d i n g a f t e r t h e stand was thinned. T o t a l g r a s s c o v e r was 42$. E l e v e n s p e c i e s o f f o r b s were r e c o r d e d ; h e a r t - l e a v e d a r n i c a ( A r n i c a c o r d i f o l i a ) covered 8 $ and t i m b e r m i l k v e t c h covered 6$. The t o t a l c o v e r by f o r b s was 22$. Shrubs formed a major p o r t i o n o f t h e u n d e r s t o r y ; b e a r b e r r y covered l 8 $ , s p i r a e a 12$ and Rocky Mountain j u n i p e r ( J u n i p e r u s scopuiorum) covered 8 $ . b. The L a r c h S i t e The l a r c h s i t e on E s t e l l a Mountain i s l o c a t e d i n a m o i s t draw a t the 4,220 ft. elevation. Logged In 1952 t h i s s i t e i s c u r r e n t l y dominated by l a r c h ; t h e u n d e r s t o r y i s a r a p i d l y d e v e l o p i n g stand o f young Douglas f i r . The e x i s t i n g l a r c h t r e e s a r e 6 0 t o 70 f e e t h i g h , have a f o r e s t canopy cover o f 7 2 $ and a pre-modal age of 125 y e a r s . The g r a s s u n d e r s t o r y i s dominated by p i n e g r a s s c o v e r i n g 5 2 $ . Ten s p e c i e s o f f o r b s had a t o t a l cover o f 2 6 $ . Heart- l e a v e d a r n i c a covered 1 7 $ , w i l d s t r a w b e r r y 2 $ and b e l l s or western covered 2 $ . stenanthium bronze (Stenanthium o c c i d e n t a l e ) Shrubs were an i m p o r t a n t component of the u n d e r s t o r y c o v e r i n g 2 5 $ o f t h e ground s u r f a c e . Spiraea 12$ and t w i n f l o w e r ( L l n n a c a b o r e a l i s ) 3$ were t h e most common s p e c i e s . c. The Lodgepole S i t e The l o d g e p o l e s i t e on E s t e l l a . i s r e p r e s e n t a t i v e F i g u r e 20. The r e g e n e r a t i n g D o u g l a s f i r s t a n d Mounts i n . on E s t e l l 8 49 o f t h i c k stands o f l o d g e p o l e p i n e which f o l l o w e d t h e f i r e of 1934. The e l e v a t i o n o f t h e s i t e i s 5 , 9 8 0 f t , and t h e pre-modal age i s 35 y e a r s . The f o r e s t canopy c o v e r was 7 1 $ i n t h i s s t a n d which had 1 , 6 3 4 stems p e r acre. P i n e g r a s s was t h e o n l y g r a s s s p e c i e s p r e s e n t , h a v i n g a ground c o v e r o f 2 9 $ . Twelve s p e c i e s o f f o r b s covered 3 7 $ . Most abundant were h e a r t - l e a v e d a r n i c a c o v e r i n g 7 $ , a s t e r ( A s t e r c o n s p l c u u s ) c o v e r i n g 1 2 $ . Shrubs o c c u p i e d 2 3 $ o f t h e ground c o v e r ; s p i r a e a and s o a p o l a l l i e were most common w i t h c o v e r s o f 7 $ each. Bearberry, rose and t w i n f l o w e r were a l s o p r e s e n t . 5. E s t e l l a Mountain N o n - f o r e s t e d a. Sites S e r a i Fescue S i t e The s e r a i f e s c u e s i t e on E s t e l l a i s l o c a t e d a t the 5,960 f t elevation. S t a n d i n g and f a l l e n t r e e s o f t h e burned w h i t e b a r k p i n e f o r e s t remain a t t h e s i t e . p i n e has f a i l e d t o e s t a b l i s h b u t s e v e r a l w h i t e b a r k s e e d l i n g s were found i n t h e m a c r o p l o t . Lodgepole pine The pre-modal age o f t h i s s i t e i s z e r o , i n terms o f r e f o r e s t a t i o n , however a burn o c c u r r e d 35 y e a r s ago. The g r a s s community a t t h i s s i t e i s c u r r e n t l y dominated by rough f e s c u e which has a cover o f 4 l $ . P i n e g r a s s i s a l s o p r e s e n t , p r o b a b l y as a r e s u l t of the previous f o r e s t , covering 7 $ . Canada b l u e g r a s s and an u n i d e n t i f i e d F e s t u c a spp. were p r e s e n t i n t r a c e Figure 22. The l o d g e p o l e p i n e stand on E s t e l l a Mountain. The opening i n the foreground i s the r e s u l t o f t h e road c u t . 52 amounts. The t o t a l c o v e r b y g r a s s was 48$. abundant; seventeen Porbs were s p e c i e s had a t o t a l c o v e r o f 4l$. Common s p e c i e s were w h i t e penstemon w i t h 16$ c o v e r , yarrow 6$ and locoweed ( O x y t r o p i s c a m p e s t r i s ) w h i c h covered 3$ of t h e ground s u r f a c e . Shrubs were n o t abundant w i t h a t o t a l cover o f 11$; b e a r b e r r y c o v e r i n g 5 $ , was most common, w h i l e s p i r a e a , Rosa spp. and w i l l o w ( S a l i x spp.) were a l s o p r e s e n t . d. The S e r a i Bluebunch Wheatgrass S i t e The. s e r a i bluebunch wheatgrass s i t e on E s t e l l a . i s l o c a t e d on a g r a s s y f i n g e r o f v e g e t a t i o n i n t h e lodgep o l e p i n e f o r e s t a t an e l e v a t i o n o f 6,200 f t . Tree r e - g e n e r a t i o n d i d n o t f o l l o w t h e burn o f 1934 and t h e s i t e i s dominated by rough f e s c u e b u t i s unique because wheatgrass s p e c i e s occupy 6$ c o v e r . No bluebunch wheatgrass was found on t h e lower e l e v a t i o n f e s c u e s i t e , b u t i t o c c u r s on t h e same burn a t an e l e v a t i o n o f 4,500 f t . Bluegrass covered 4$ a t t h i s s i t e ; t h e t o t a l c o v e r by g r a s s e s was 33$. N i n e t e e n s p e c i e s o f f o r b s were r e c o r d e d , 17$ c o v e r . Common s p e c i e s were s t o n e c r o p totalling (Sedum spp.) 3$ c o v e r , yarrow 2$ c o v e r and n a r r o w - l e a v e d p a r s l e y . (Lomatium t r i t e r n a t u r n ) covered 3$. No shrubs were found on t h e s i t e , b u t s c a t t e r e d clumps o f b e a r b e r r y were Figure 23. The s e r a i f e s c u e s i t e . N o t i c e the burned stumps o f t h e w h i t e - b a r k p i n e f o r e s t w h i c h e x i s t e d p r i o r t o the 1934 f i r e . This photog r a p h was t a k e n " d o w n h i l l " l o o k i n g t o w a r d the f l o o r of the t r e n c h . 54 observed i n the v i c i n i t y . B. F l o r i s t i c Dynamics 1. The Premier Ridge Sites. The t h r e e u n f o r e s t e d s i t e s on Premier were e s t a - b l i s h e d on two v e g e t a t i o n t y p e s , t h e r e l i c t b l u e b u n c h wheatgrass g r a s s l a n d and t h e b l u e g r a s s - b i t t e r b r u s h community. The wheatgrass g r a s s l a n d was p r o b a b l y i n i t i a t e d by the r e - moval o f the t i m b e r from the a l r e a d y f a i r l y open f o r e s t , o f which b l u e b u n c h wheatgrass would have been an member o f t h e u n d e r s t o r y community. f o r e s t has a l l o w e d t h i s important The removal o f the s i t e to s h i f t dynamically toward the f l o r i s t i c c h a r a c t e r i s t i c s o f the n a t u r a l g r a s s l a n d In the a r e a . The u n d e r s t o r y o f the b l u e g r a s s - n e e d l e g r a s s site and the b i t t e r b r u s h s i t e p r o b a b l y d i d not c o n t a i n any b l u e g r a s s s p e c i e s a t t h e time o f l o g g i n g . p r o x i m i t y of these s i t e s However, the relative (and most o f the b l u e g r a s s - b i t t e r b r u s h community) t o water and t h e i r relative flatness, p r o b a b l y s u b j e c t e d them to heavy c o n s t a n t g r a z i n g f o l l o w i n g l o g g i n g and the f i r e s which swept the a r e a . Consequently, Canada b l u e g r a s s and Kentucky b l u e g r a s s were a b l e t o dominate the s i t e r a t h e r than b l u e b u n c h wheatgrass which would r e q u i r e more time and stantial development. lighter g r a z i n g p r e s s u r e f o r sub- • 55 F i g u r e 24. The s e r a i b l u e b u n c h w h e a t g r a s s s i t e . The b u r n e d f o r e s t was one o f w h i t e - b a r k p i n e . The living t r e e s i n the p i c t u r e are lodgepole p i n e . Notice t h e e f f e c t o f a s p e c t on t h e p a t t e r n of t h e r e generation . 56 Rough f e s c u e may have been a member o f t h e f o r e s t u n d e r s t o r y , however i t s extreme s e n s i t i v i t y t o heavy g r a z i n g has e f f e c t i v e l y removed i t from t h e u n f o r e s t e d s i t e s were s t u d i e d on P r e m i e r R i d g e . which The r e l i c t bluebunch wheat- g r a s s s i t e on P r e m i e r i s t h e s i t e most r e p r e s e n t a t i v e o f the n a t u r e o f t h e s u c c e s s i o n when u n a f f e c t e d by heavy g r a z i n g by domestic, s t o c k . C o n s e q u e n t l y , t h i s s i t e was s e l e c t e d t o r e p r e s e n t t h e open u n f o r e s t e d a r e a s o f t h e ridge. The p l a c e , o f t h e b l u e g r a s s - b i t t e r b r u s h community and i t s r e l a t i o n s h i p t o t h e f l p r i s t i c dynamics w i l l be d i s c u s s e d i n a l a t e r s e c t i o n on t h e e f f e c t o f g r a z i n g on community c o m p o s i t i o n and p r o d u c t i v i t y . a. Grasses The r e l i c t bluebunch wheatgrass i s t i c o f u n f o r e s t e d communities s i t e i s character- which developed following l o g g i n g and b u r n i n g under a r e l a t i v e l y moderate g r a z i n g regime. Bluebunch wheatgrass dominates ground c o v e r o f about 5 0 $ i s common. o t h e r common g r a s s . t h e s i t e and a Junegrass i s t h e o n l y As r e f o r e s t a t i o n commences an immediate r e d u c t i o n i n t h e bianchgrasses i s n o t e d ; t h e s e s p e c i e s r e main uncommon o r may c o m p l e t e l y d i s a p p e a r from t h e unders t o r y , u s u a l l y r e a p p e a r i n g i n c l i m a x f o r e s t s as t h e f o r e s t canopy opens. The l e v e l o f abundance a c h i e v e d i n t h e s e c l i m a x stands I R about 20$ o f t h a t a c h i e v e d on t h e un- 57 forested sites. Junegrass a l s o becomes l e s s abundant as t h e f o r e s t develops r e a p p e a r i n g i n t h e c l i m a x f o r e s t community, where i t may a c h i e v e 5 0 $ o f i t s former abundance. P i n e g r a s s i s v e r y uncommon on t h e open s i t e s , however i t i n c r e a s e s r a p i d l y as f o r e s t r e g e n e r a t i o n commences. On m o i s t s i t e s p i n e g r a s s may r e a c h a ground c o v e r o f 4 0 $ ' or more i n s p i t e o f a heavy f o r e s t canopy. The t o t a l ground c o v e r by a l l s p e c i e s o f g r a s s e s d e c r e a s e s increasing with s t a n d age. T a b l e s I and I I and F i g u r e 2 5 d e p i c t t h e t r e n d s o f g r a s s ground c o v e r as c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy c o v e r change, b. Forbs The c h a r a c t e r i s t i c s t a n d age and t h e f o r e s t canopy c o v e r seemed t o have no pronounced e f f e c t on t h e total,abundance o f f o r b s ( F i g s . 26, 27, 28 and 29). v i d u a l s p e c i e s show s t r o n g p r e f e r e n c e f o r c e r t a i n canopy t y p e s . nodding and 27). Indi- forest Yarrow, sedge (Carex s p p . ) , p u s s y t o e s , o n i o n and w i l d s t r a w b e r r y a r e s c i o p h y t e s ( F i g s . 26 Balsam r o o t i s a h e l i o p h y t e w h i l e t i m b e r m i l k v e t c h seems t o be a s c i o p h y t e ( F i g . 28). The number o f f o r b s p e c i e s p r e s e n t a t t h e v a r i o u s s i t e s was r e l a t i v e l y c o n s t a n t , except f o r t h e r e l i c t bluebunch which had o n l y 5 s p e c i e s o f f o r b s . wheatgrass In the climax f o r e s t f o r b s were most common, c o m p r i s i n g 21$ o f t h e ground cover. site F i g u r e 25. The abundance o f s e v e r a l s p e c i e s o f g r a s s e s on Premier Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. m i D itmsm » Rough f e s c u e B v Pinegrass Bluebunch wheatgrass 50 40 30 20 10 v i \ a 10 20 30 4o 50 60 70 8o 90 C h a r a c t e r i s t i c Stand 50 40 CD |> O o ^ 30 20 10 F o r e s t canopy % o no Age 130 280 59 Table I The i n f l u e n c e o f c h a r a c t e r i s t i c stand age on the s p e c i e s dynamics o f the u n d e r s t o r y g r a s s s p e c i e s e x p r e s s e d as p e r c e n t ground c o v e r . F o r e s t stand 0 22 Grass sp. Bluebunch wheatgrass 51 . Junegrass ". • 9 Needlegrass Table I I 100 1 ;8 • 2 4 ... 11 2 1 5 1 .i 280 5. T '5 42 29 39 29 43 22 18 54 35 43 28 35 T Pinegrass T o t a l ground c o v e r by g r a s s e s 80 "95 65 '•••3 . 11 Rough f e s c u e 55 age 60 4l 46 The i n f l u e n c e of f o r e s t canopy cover on the p e r c e n t ground c o v e r of the g r a s s component o f the u n d e r s t o r y % F o r e s t canopy cover Grass sp. Bluebunch wheatgrass 0 9 Needlegrass 1 5 49 5 1 49 56 4 2 3 8 T 1 43 39 43 4l 42 18 29 22 5 29 54 36 35 28 46 T Pinegrass T o t a l ground c o v e r by g r a s s spp. 11 38 11 1 51 Rough f e s c u e Junegrass 26 60 71 78 2 6o c. Shrubs The abundance o f shrubs on the u n f o r e s t e d s i t e s was v a r i a b l e , and d i r e c t l y r e l a t e d t o g r a z i n g p r e s s u r e . F i g u r e 30 and T a b l e I I I d e p i c t the r e l a t i o n s h i p between c h a r a c t e r i s t i c s t a n d age and shrub abundance. Shrubs i n - c r e a s e d s l i g h t l y as f o r e s t r e g e n e r a t i o n began, dropped o f f i n dense, middle-aged s t a n d s and began t o r e a p p e a r i n mature and c l i m a x f o r e s t s . The e f f e c t o f f o r e s t canopy on the p e r c e n t ground c o v e r o f shrubs i s shown i n T a b l e I I I and F i g u r e 30. Shrubs were v a r i a b l e i n c o v e r on the u n f o r e s t e d s i t e s and I n c r e a s e d s l i g h t l y i n the m i d d l e canopy r a n g e s , but beyond a 50$ canopy c l o s u r e shrubs d e c r e a s e d s h a r p l y , except on the n o r t h e a s t s l o p e (mature f i r s i t e , 73$ canopy). B i t t e r b r u s h decreased r a p i d l y w i t h f o r e s t r e g e n e r a t i o n and reappeared i n t h e c l i m a x f o r e s t . Bearberry, u s u a l l y p r e s e n t I n v e r y s m a l l amounts I n u n f o r e s t e d s i t e s , i n c r e a s e d s h a r p l y i n middle-aged stands and i n t h e m i d d l e canopy ranges. 2. Estella a. Mountain Grasses The t r e n d s e s t a b l i s h e d f o r t h e P r e m i e r Ridge d a t a appear t o h o l d f o r the E s t e l l a s i t e s . Rough f e s c u e f r e - q u e n t l y r e p l a c e s bluebunch wheatgrass as t h e dominant bunchgrass on u n f o r e s t e d s i t e s . 61 F i g u r e 26. The abundance o f s e v e r a l s p e c i e s o f f o r b s on Premier R i d g e , as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age. o denotes abundance i n n a t u r a l g r a s s l a n d community 4 3 2 1 4 3 2 1 Yarrow 4 3 2 1 CD > o o 4 3 2 1 4 3 2 1 Wild Hyi».i».MIwi. I I U I H I . . I I I 1 I H . . .UI..IIII^... • "I'm,; I mn 1 nii; Onion •• Wild Strawberry / 4 3 2 1 Penstemori 1—m—1 0 20 -i 4o 1 60 i 1 80 r 1—8—J—rV » *i 100 120 C h a r a c t e r i s t i c Stand Age 280 62 Figure 27. The abundance o f s e v e r a l s p e c i e s o f f o r b s on P r e m i e r Ridge as i n f l u e n c e d by f o r e s t canopy. o denotes l e v e l i n n a t u r a l g r a s s l a n d F o r e s t Canopy % community 63 Figure 28. The abundance o f t i m b e r m i l k v e t c h and b a l s a m - r o o t on P r e m i e r Ridge as i n f l u e n c e d by f o r e s t canopy. o denotes l e v e l i n n a t u r a l g r a s s l a n d community l4 Timber m i l k 12 vetch 10 8 6 4 2 CD > o o 12 10 8 6 4 2 T T 20 30 i 4o I 50 J 6o F o r e s t Canopy % i 70. 1 r 8o 90 64 Figure 29. The abundance o f f o r b s on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. o denotes l e v e l i n n a t u r a l g r a s s l a n d community 35 30 25 CD 20 O 15 > o 10 5 T — I — r — i — i o 20 4o a — i — n — r i 6o 8o Characteristic IOO r 120 Stand A g e r I 280 65 F i g u r e 3 0 . . The abundance o f dwarf shrubs on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. 50 4o 0 > o o 30 10 10 T 0 20 "T" 40 i \ 60 T 80 Characteristic T—r .100 Stand F o r e s t Canopy % n—1—T/ 120 140 Age ~T~ 280 T a b l e I I I The abundance o f shrubs on t h e Premier Ridge s i t e s , i n r e l a t i o n t o c h a r a c t e r i s t i c stand age and f o r e s t canopy. C h a r a c t e r i s t i c Stand Age F o r e s t Canopy % 0 0 Spirea Rose 0 0 0 0 1.5 3.0 22 2b 55 5b 2.3 4.4 4.8 2.5 1.0 1.2 65 78 80 49 95 72 1.4 26.3 0.1 Bearberry Bitterbrush Soapolallie T o t a l % cover by shrubs 280 3b 1 1.2 0.6 0.9 0.9 Oregon Grape Saskatoon 100 49 2.0 2.4 3.8 7.1 0.5 11.6 16.9 3.6 25.0 16.6 1.3 7-0 20 2.5 7-3 4.3 11.2 3.7 10.1 2.2 17.1 l6.5 2.2 3-7 0.4 1.0 8.6 29.4 4 l . 8 34.7 15.0 1.6 17.5 20.7 11.6 28.1 31-5 35.8 67 F i g u r e 31 shows the e f f e c t o f c h a r a c t e r i s t i c stand age on the s p e c i e s abundance of g r a s s e s . On most u n f o r e s t e d a r e a s , a bunchgrass dominates the community ( 2 0 - k0% cover). Pinegrass i s present i n t r a c e amounts on these open a r e a s and i n c r e a s e s i n abundance as f o r e s t r e g e n e r a t i o n commences. The bunchgrasses a r e reduced i n abundance or d i s a p p e a r s o l e grass present The completely. P i n e g r a s s may be i n mature f o r e s t s t a n d s . e f f e c t o f f o r e s t canopy on g r a s s abundance on E s t e l l a Mountain i s shown i n FIgtire 3 1 . The pa.ttern i s s i m i l a r t o the one d e s c r i b e d f o r c h a r a c t e r i s t i c age. The the stand time r e q u i r e d f o r the f o r e s t t o d e v e l o p on Estella, i s c o n s i d e r a b l y l e s s than i s r e q u i r e d on Premier Ridge. b. Forbs The abundance o f f o r b s on E s t e l l a Mountain, as assessed by ground c o v e r , f o l l o w s a p a t t e r n s i m i l a r to t h a t found on P r e m i e r Ridge. C h a r a c t e r i s t i c stand age and f o r e s t canopy have l i t t l e e f f e c t on t o t a l f o r b abundance ( F i g . 3 2 ) . T h i r t y - n i n e s p e c i e s of f o r b s were r e c o r d e d a t the Estella sites. The highest s i t e , 6,200 g r e a t e s t number of f o r b s p e c i e s , 1 9 . s u f f i c i e n t numberof s i t e s on five f t . a l s o had There was not the a E s t e l l a Mountain t o a s c e r t a i n which f o r b s were h e l i o p h y t e s and which were s c i o p h y t e s . c. Shrubs There was no d e f i n i t e t r e n d i n the shrub d a t a when 68 Figure.31. The abundance o f s e v e r a l s p e c i e s o f g r a s s e s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. Rough f e s c u e B B Pinegrass v Bluebunch wheatgrass 69 T a b l e IV The abundance o f s e v e r a l s p e c i e s o f measured by p e r c e n t ground c o v e r on Mountain. Tabulated w i t h reference c h a r a c t e r i s t i c s t a n d age and f o r e s t C h a r a c t e r i s t i c Stand F o r e s t Canopy Rough f e s c u e Age 0 0 40.9 Bluebunch wheatgrass 6.9 Bluegrass 0.1 by 25 35 22.3 35 71 .125. 72 0.5 6.2 Pinegrass T o t a l % cover grasses 0 0 g r a s s e s as Estella to canopy. 48.3 41.7 29.0 51.7 42.2 29.0 51.7 4.4 32.9 70 T a b l e V. The abundance o f f o r b s as measured by p e r c e n t ground c o v e r on E s t e l l a M o u n t a i n , r e c o r d e d re-.--. l a t i v e t o c h a r a c t e r i s t i c s t a n d age and f o r e s t . canopy. : C h a r a c t e r i s t i c Stand Age F o r e s t Canopy 0 / 0 . 0 0 25 35 35 71 1 T Pussytoes Fireweed T Arnica c o r d i f o l i a T Sedges T Mountain 1.7 T 8.1 6.7 1.9 3.0 1.8 P y r o l a secunda Yarrow Penstemon p r o c e r u s Locoweed 16.8 3.2 death Hedysarum s u l p h u r esc ens 125 72 . 3.3 LO 5.7 1.6 15.6 1.2 3.4 Timber m i l k v e t c h 1.6 T T 6.2 T 1.7 T T Wild strawberry 1.9 T Bronze b e l l s 1.6 Twinflower 2.7 3.7 Stonecrop 1.1 Nodding o n i o n Narrow l e a v e d p a r s l e y 2.5 Mountain p h a c e l i a 1.5 Aster conspicuus 8.3 Number o f o t h e r s p e c i e s present i n t r a c e 1.0) abundance 7 forbs . Ground c o v e r by 2.0 10 =4 41.8 18.9 22.4 12.0 2 36.5 1.9 5 38.2 71 compared w i t h c h a r a c t e r i s t i c stand age and f o r e s t Bitterbrush canopy. i s not found on t h e E s t e l l a s i t e s , b e i n g r e - s t r i c t e d t o e l e v a t i o n s below 4,000 ft. In g e n e r a l , shrub abundance was about t h e same magnitude on Premier Ridge. total as t h a t found The abundance o f shrubs on E s t e l l a Mountain i s l i s t e d i n T a b l e V I . Table V I . S t a t i s t i c s f o r Shrub Abundance on E s t e l l a Mountain Years C h a r a c t e r i s t i c Stand F o r e s t Canopy Age 0 0 0 0 25 35 Spiraea 2.7 - 12.0 6.9 11.7 Rose 1.8 8.7 0.1 1.0 1.5 Bearberry 5.2 - 18.1 4.1 0.1 6.9 Soapalallie 35 71 125 72 Unknown sp. 7.0 T o t a l shrub c o v e r C. Productivity 1. Premier Ridge a. Grass 9.7 8.7 30.3 18.9 20.2 Productivity The t o t a l p r o d u c t i v i t y o f g r a s s was h i g h e s t on the open s i t e s and lowest on t h o s e s i t e s w i t h dense c a n o p i e s and r a p i d l y growing t r e e s . The e f f e c t which f o r e s t r e - g e n e r a t i o n has on g r a s s p r o d u c t i o n i s e v i d e n t i n F i g u r e 3 3 . 72 Figure 32. The abundance o f f o r b s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. 50 40 > O O 30 J 20 10 0 T — r 20 u 4o i i—T~T—r 6o 280 8o Characteristic Stand Age F o r e s t Canopy % 73 Average p r o d u c t i o n o f g r a s s e s on the t h r e e open s i t e s 53 gm/m ( 4 7 2 T b / A C ) . was Twenty y e a r s a f t e r the i n i t i a l 2 stages o f f o r e s t r e g e n e r a t i o n , g r a s s p r o d u c t i v i t y dropped t o 6 2 $ o f i t s former l e v e l . F i f t y - f i v e years f o l l o w i n g forest r e g e n e r a t i o n o n l y 2 5 $ of the open a r e a p r o d u c t i v i t y i s a c h i e v e d by g r a s s e s . " P r o d u c t i o n o f g r a s s remains low, the stand b e g i n s to,thin. duction r i s e s s l i g h t l y . As the f o r e s t ages, g r a s s pro- In t h e s e c l i m a x f o r e s t stands 4 0 $ o f the g r a s s p r o d u c t i o n o f open areas may be until about attained. A s i m i l a r t r e n d i s noted when f o r e s t canopy cover i s used as a v a r i a b l e i n measuring g r a s s (Fig- 33). productivity At a f o r e s t canopy o f 2 6 $ , g r a s s productivity dropped to 5 1 $ of the open areas and a t a f o r e s t canopy o f 5 0 $ p r o d u c t i o n dropped t o 3 8 $ . increasing founding S p e c i e s changes occur w i t h shade and must t h e r e f o r e be regarded as a con- factor. b. Forb Productivity Forb abundance i s o f t e n reduced i n c l i m a x g r a s s lands and g r e a t l y i n c r e a s e s i n secondary g r a z i n g s u c c e s s i o n s . D e s p i t e d i f f i c u l t i e s i n a n a l y s i n g f o r b performace and ence i n f l o r i s t i c s t u d i e s , warrants special occurr- t h e i r importance t o g r a z e r s categorization. F i g u r e 34 r e f l e c t s t h e v a r i a b i l i t y ance and p r o d u c t i o n on the open a r e a s . i n f o r b abund- Average p r o d u c t i o n 7h F i g u r e 33. The p r o d u c t i v i t y o f g r a s s on Premier Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. F o r e s t Canopy % 75 for the t h r e e s i t e s was 15 gm/m ( l 4 7 2 Ib/AC.). S i x t y - f i v e y e a r s a f t e r the onset o f f o r e s t r e g e n e r a t i o n , f o r b abundance dropped to 17$ o f i t s p r e v i o u s level. Beyond e i g h t y y e a r s , f o r b p r o d u c t i o n i n c r e a s e s i n c l i m a x stands (over 2 5 0 y e a r s ) may and a c t u a l l y exceed the p r o d u c t i o n a c h i e v e d on the open a r e a s . There i s l i t t l e change i n f o r b p r o d u c t i o n the f o r e s t canopy exceeds 5 0 $ cover p o i n t , p r o d u c t i v i t y decreases may y i e l d abundance o f f o r b s . trend i n F i g . 15, pine (Fig. 34). Beyond t h i s a l t h o u g h an o c c a s i o n a l s i t e Tne l a r g e d e v i a t i o n from the a t 3 8 $ , r e p r e s e n t s t h e c l i m a x ponderosa stand. c. Dwarf Shrub P r o d u c t i v i t y No m e a n i n g f u l t r e n d s a r e d i s c e r n a b l e i n the dwarf shrub d a t a f o r Premier Ridge. Changes i n p r o d u c t i v i t y a r e masked by changes i n s p e c i e s c o m p o s i t i o n and s o i l at until each s i t e . moisture The r e l a t i v e c o n t r i b u t i o n o f these p l a n t s i s s m a l l , t h e i r p r o d u c t i o n i s shown i n F i g u r e 3 5 . d. B e a r b e r r y Produc t i v i t y The e f f e c t of c h a r a c t e r i s t i c stand age on the annual p r o d u c t i v i t y o f b e a r b e r r y i s shown i n F i g u r e 3 6 . P r o d u c t i o n on open areas i s r e l a t i v e l y low, but r a p i d l y as f o r e s t r e g e n e r a t i o n commences. increases Beyond an age o f 50 y e a r s , most stands have become s u f f i c i e n t l y dense to cause some r e d u c t i o n i n b e a r b e r r y p r o d u c t i o n . As 76 F i g u r e 34. The p r o d u c t i v i t y o f f o r b s on P r e m i e r RIdg as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. 70 9 —I—\—j—t—\ 0 20 40 * \ \ u—T°T—i—i—i—i 60 80 100 C h a r a c t e r i s t i c Stand Age 70 C\J i ^ 60 F o r e s t Canopy % / 120 —r 280 77 n a t u r a l t h i n n i n g commences a t ages beyond 1 0 0 y e a r s , b e a r b e r r y p r o d u c t i o n i n c r e a s e s and i s f r e q u e n t l y a major component o f t h e u n d e r s t o r y v e g e t a t i o n o f t h e c l i m a x community. P r o d u c t i o n o f b e a r b e r r y i s low on t h e open s i t e s , r i s e s u n t i l canopy covers o f l e s s than 5 0 $ a r e reached then d e c l i n e s under canopies g r e a t e r than 5 0 $ ( P i g . 3 5 ) . e. Bitterbrush Productivity The open s i t e s a n n u a l l y produce v e r y l a r g e q u a n t i t i e s of b i t t e r b r u s h . Some v a r i a b i l i t y among open s i t e s r e s u l t s from d i f f e r e n c e s i n g r a z i n g these intensity. The onset o f f o r e s t r e g e n e r a t i o n s e v e r e l y depresses brush p r o d u c t i o n . Twenty-five bitter- y e a r s a f t e r r e g e n e r a t i o n had commenced b i t t e r b r u s h p r o d u c t i o n was l e s s than 1/3 o f i t s former l e v e l . F i f t y y e a r s l a t e r , p r o d u c t i o n was n e g l i g i b l e and t h i s l e v e l w i l l be m a i n t a i n e d u n t i l t h e f o r e s t c l i m a x i s reached I n w h i c h b i t t e r b r u s h u s u a l l y becomes more abundant. P r o d u c t i o n i n t h e c l i m a x f o r e s t compares f a v o u r - a b l y w i t h a v e r a g e open s i t e s . These t r e n d s a r e shown i n Figure 37. The r e l a t i o n s h i p between b i t t e r b r u s h p r o d u c t i o n and f o r e s t canopy i s shown i n F i g u r e 3 7 - P r o d u c t i o n , which i s h i g h on t h e open s i t e s d e c l i n e s s t e a d i l y , except f o r an abrupt r e d u c t i o n a t 3 8 $ which r e p r e s e n t s t h e c l i m a x stand 78 Figure 35. The a n n u a l p r o d u c t i v i t y o f dwarf shrubs on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. F o r e s t Canopy % 79 36. The a n n u a l p r o d u c t i v i t y o f b e a r b e r r y on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. F o r e s t Canopy % 80 o f p i n e and f i r . Beyond a f o r e s t canopy o f 5 0 $ , b i t t e r - b r u s h p r o d u c t i o n i s v e r y low, w h i l e a . f o r e s t canopy o f 2 6 $ i s s u f f i c i e n t t o lower p r o d u c t i o n t o 3 9 $ o f i t s former level.' f. Soapoiallie Productivity The p r o d u c t i o n o f s o a p o i a l l i e v a r i e s l i t t l e s e r a i stage and changes r e l a t i v e l y l i t t l e w i t h the one with ex- c e p t i o n t h a t on c e r t a i n s i t e s I t i s e x c e p t i o n a l l y p r o d u c t i v e and abundant j u s t b e f o r e and d u r i n g the stages forest regeneration. S o a p o i a l l i e p r e f e r s moist s i t e s w i t h s o i l moisture w e l l maintained and of through the growing season, i s not common i n pure stands o f ponderosa p i n e . F i g u r e 38 shows t h e p r o d u c t i v i t y of s o a p o i a l l i e under v a r i o u s canopies. forest S i n c e t h i s s p e c i e s f r e q u e n t l y grows under major b r e a k s o r openings i n the canopy, an average canopy cover may not be the most e f f e c t i v e way preference. to measureits site Canopy covers o f 2 0 $ to 4-0$ e x h i b i t the h i g h e s t annual t w i g p r o d u c t i o n on an a r e a b a s i s . 2. E s t e l l a Mountain a. Grass Productivity The p r o d u c t i o n o f g r a s s on E s t e l l a Mountain f o l l o w e d a p a t t e r n s i . m i l a r to Premier Ridge, but was than t h a t o f t h e lower a r e a . The somewhat h i g h e r e f f e c t of c h a r a c t e r i s t i c stand age on g r a s s p r o d u c t i o n i s shown In F i g u r e 3 9 . Pro- • 8i ;.. The a n n u a l p r o d u c t i v i t y o f b i t t e r b r u s h ( t w i g s and t h e i r l e a v e s o n l y ) on P r e m i e r Ridge as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. I i I I I I l 20 40 60 Characteristic 1—7 10 I I I I 80 Stand 100 120 Age 20 F o r e s t Canopy % t e x t f o r e x p l a n a t i o n of t h i s p o i n t I / 280 82 Figure 38. The a n n u a l p r o d u c t i v i t y o f s o a p o i a l l i e ( t w i g s l e a v e s ) as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d and f o r e s t canopy. P r e m i e r Ridge s i t e s . F o r e s t Canopy % and age 83 d u c t i o n i s h i g h on open s i t e s , 54 gm/m 2 (529 l h / a c . ) and d e c l i n e s r a p i d l y as f o r e s t r e g e n e r a t i o n commences. After 35 y e a r s g r a s s p r o d u c t i o n i s 28$ o f t h a t a c h i e v e d on open areas. P r o d u c t i o n i n c r e a s e s as stands mature and 62$ o f the open area, p r o d u c t i o n i n 125 reaches years. Grass p r o d u c t i o n d e c l i n e s s t e a d i l y w i t h i n c r e a s i n g f o r e s t canopy. recorded The low l e v e l s o f p r o d u c t i o n which were f o r Premier Ridge under dense f o r e s t c a n o p i e s do not seem t o o c c u r on E s t e l l a Mountain ( F i g . 39). b. Forb P r o d u c t i v i t y The f o r b p r o d u c t i o n o f the open a r e a s on E s t e l l a Mountain i s r e l a t i v e l y h i g h , b e i n g composed o f fewer s p e c i e s than i s c h a r a c t e r i s t i c o f the lower, more h e a v i l y grazed ranges. Mean y i e l d s on open s i t e s was 18 gm/m They d e c l i n e s t e a d i l y as f o r e s t canopy and stand age increase. (l60 lb/ac.). characteristic T h i r t y - t h r e e y e a r s a f t e r the onset o f f o r e s t r e g e n e r a t i o n t h e f o r b y i e l d i s reduced b y 50$. The f o r e s t canopy a s s o c i a t e d w i t h such. a. d e c l i n e i s about 70$. Forb p r o d u c t i o n i s shown I n F i g u r e 40. c. Dwarf Shrub P r o d u c t i v i t y The r e l a t i o n s h i p between c h a r a c t e r i s t i c s t a n d age and dwarf shriib p r o d u c t i v i t y i s shown i n F i g u r e 41. v a r y from 3 t o 12 gm/m 2 (27 t o 167 Yields l b / a c . ) on theopen s i t e s and remain a t t h e s e l e v e l s f o r the f i r s t 30 t o 40 y e a r s o f tree regeneration. Y i e l d s i n o l d e r stands a r e v e r y low, 84 Figure 39. The p r o d u c t i v i t y o f g r a s s e s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. F o r e s t Canopy % 85 2 gm/m (17 l b / a c ) . There was no d i s c e r n a b l e r e l a t i o n s h i p between dwarf shrub p r o d u c t i o n and f o r e s t canopy, as shown in Figure 4 l . d. Bearberry Productivity B e a r b e r r y was v e r y abundant on one s i t e on E s t e l l a At a l l o t h e r s i t e s I t y i e l d e d Mountain. (44.5 lb/ac). l e s s than 5 gm/m 2 There*are n o t s u f f i c i e n t o b s e r v a t i o n s t o a s c e r t a i n whether t h i s i s a common phenomenon. appears t o be depressed Productivity i n open a r e a s and under v e r y dense f o r e s t c a n o p i e s , b e i n g somewhat h i g h e r a t i n t e r m e d i a t e canop i e s , as shown i n F i g u r e 4 2 . e. Bitterbrush Bitterbrush at the e l e v a t i o n s f. Productivity does n o t o c c u r on E s t e l l a Mountain a t which t h e p l o t s were Soa^polallie established. Productivity The p r o d u c t i v i t y o f s o a p o i a l l i e i s shown i n F i g u r e 43. C o m p a r a t i v e l y l i t t l e y i e l d i s a c h i e v e d on the open, r e c e n t l y burned a r e a . P r o d u c t i o n r i s e s s h a r p l y as the f o r e s t b e i n g s t o r e g e n e r a t e and u s u a l l y remains h i g h under dense f o r e s t canopies. conditions S o a p o i a l l i e seems t o s u r v i v e under t h e s e by growing near major b r e a k s i n t h e f o r e s t canopy. D. O v e r s t o r y Community Composition 1. Premier Ridge The seven f o r e s t e d s i t e s on Premier Ridge range i n 86 F i g u r e 40. The p r o d u c t i v i t y o f f o r b s on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t ca.nopy. F o r e s t Canopy % 87 F i g u r e 41. 12 OJ g W C o •H o T) O U PH 10 The p r o d u c t i v i t y o f dwarf shrubs on E s t e l l a Mountain as I n f l u e n c e d by c h a r a c t e r i s t i c stand age and f o r e s t canopy. 1 8 6 4 2 T 0 J—"T 1.0 20 S 30 1 40 f—\ 50 60 F o r e s t Canopy $ T—1 80 90 S 100 1 120 88 age from 22 t o 280 y e a r s , spanning a f o r e s t canopy cover 26$ t o 78$. The most dense s t a n d , 3,4-59 stems from' per a c r e , a l s o had the h i g h e s t f o r e s t canopy, 78$, and i s r e p r e s e n t a t i v e of the l o d g e p o l e p i n e f i r e s e r e s o f the s o u t h e r n Rocky Mountain Trench. The c l i m a x ponderosa p i n e s i t e b y compari- son had o n l y 74 stems p e r a c r e w i t h a. f o r e s t canopy o f In g e n e r a l , ponderosa 38$. p i n e stands occupy more x e r i c s i t e s than the Douglas f i r and tend t o have fewer stems per a c r e and more open c a n o p i e s . In a d d i t i o n , the f i r s i t e s tend t o be c l u s t e r e d near the n o r t h e r n end o f the r i d g e whi.ch i s m e s i c , l a r g e l y due t o the m i c r o c l i m a t i c e f f e c t s o f a c o o l e r exposure. The o n l y western l a r c h o c c u r s i n a s s o c i a t i o n w i t h f i r . s t a n d s a t the n o r t h end o f t h e ridge. 2. E s t e l l a . Mountain The t h r e e f o r e s t s i t e s on E s t e l l a Mountain r e p r e s e n t a t i v e o f f o r e s t s o f warmer exposure, the southwestern a s p e c t s from tion. 4,000 to 7,000 are particularly feet i n eleva- The c h a r a c t e r i s t i c stand age v a r i e s from 25 t o 125 y e a r s w i t h a f o r e s t canopy range o f 35$ t o 72$. The E s t e l l a Mountain f o r e s t s do not tend t o t h i n t h e i r canopy n a t u r a l l y as t h e y mature, but remain r e l a t i v e l y dense, u n l i k e those o f Premier Ridge. Consequently o n l y the youngest forest ( l e s s than 25 y e a r s o l d ) e x h i b i t c o m p a r a t i v e l y low f o r e s t 89 F i g u r e 42. , s OJ 6 ^—' C o 120 100 80 •H -p O 6o •a 4o o u P-, The a n n u a l p r o d u c t i v i t y o f b e a r b e r r y on E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age and f o r e s t canopy. 20 1 -.1 o \ 20 \ s f 4o s i—I 6o Characteristic I 1 8o Stand I IOO m 120 Age 120 OJ 6 100 80 o •H -p O • 3 •a o 60 4o 20 e e 1—1—I 8o F o r e s t Canopy % 90 ioo 90 F i g u r e 43. The a n n u a l p r o d u c t i v i t y o f s o o p o l a l l i e ( t w i g s and l e a v e s ) as i n f l u e n c e d by c h a r a c t e r i s t i c stand age and f o r e s t canopy. E s t e l l a s i t e s . Table V I I S i t e s t a t i s t i c s f o r t r e e s Premier Ridge 1 9 6 9 . Young Douglas Fir Mid. Douglas Fir Mature Douglas Fir Young Ponderosa Pine C h a r a c t e r i s t i c Stand Age 22 55 95 80 100 280 65 F o r e s t Ca;nopy % 26 56 73 49 49 38 78 No. t r e e s p e r a c r e 1930 605 331 958 Mid. Ponderosa Pine 261 No, t r e e s i n m a c r o p l o t 443 139 76 220 60 No. Douglas f i r 438* 135* 76* 142 13 3 No. Ponderosa p i n e No. Lodgepole p i n e 3 No. L a r c h 2 * denotes c u r r e n t dominants. 67 1 1 47* Climax Ponderosa Pine Lodgepole Pine 47 3459 17 794 4 133 .13* 328 333* --o 92 canopy c o v e r l e s s than 3 5 $ . S e l e c t i v e l o g g i n g has the c a n o p i e s o f the r e g e n e r a t i n g f i r s i t e and the site. The thinned larch e f f e c t of t h i s t h i n n i n g i s s i m i l a r to the n a t u r a l t h i n n i n g seen on Premier R i d g e , but q u i t e d i f f e r e n t from t h e e f f e c t s o f c l e a r - c u t l o g g i n g . Selective logging on E s t e l l a has t r i g g e r e d a c t i v e r e g e n e r a t i o n o f Douglas f i r a t b o t h the a f o r e m e n t i o n e d The sites. l o d g e p o l e p i n e s i t e r e s u l t s from a hot which burned up t h e w e s t e r n exposure i n 1931. The fire of E s t e l l a Mountain l o d g e p o l e s i t e i s on an a r e a p r e v i o u s l y f o r e s t e d by w h i t e - b a r k e d p i n e . T h i s s t a n d c o n s t i t u t e s the densest f o r e s t s i t e on the mountain, w i t h 1 , 6 3 4 stems p e r a c r e , the l o w e s t b e i n g the r e g e n e r a t i n g f i r s i t e w i t h 5 5 3 stems per a c r e . The f o r e s t stands on E s t e l l a tend t o be composed l a r g e l y o f a s i n g l e s p e c i e s , a t l e a s t initially. T h i s i s e s p e c i a l l y t r u e f o r t h e l o d g e p o l e a c r e s which follow fires. E. S i t e H i s t o r y and the Path o f S u c c e s s i o n on Premier In p r i s t i n e times the west and southwest Ridge slopes o f Premier Ridge were l a r g e l y covered w i t h mature, c l i m a x stands o f ponderosa p i n e and Douglas f i r . Moist northern and n o r t h e a s t e r n s l o p e s were e s t a b l i s h e d t o Douglas f i r and l a r c h , f r e q u e n t l y i n dense s t a n d s . As a f o r e m e n t i o n e d , l o g g i n g began on Premier Ridge 93 Table V I I I S i t e s t a t i s t i c s f o r t r e e s E s t e l l a Mountain 1 9 6 9 . Regen. Douglas Elevation Characteristic 4500 Stand Age Fir W. L a r c h 4500 Lodgepole Pine 6000 25 125 35 35 72 71 No. t r e e s p e r a c r e 553 1255 1634 No. t r e e s i n s i t e 127 288 No. Douglas F i r 121* 185 No. Lodgepole P i n e 3 19 No. L a r c h 3 F o r e s t Canopy f> * denotes c u r r e n t dominants. 1 84 375 375* 94 about 1910 and was w e l l underway by 1 9 2 0 . The mature f o r e s t s o f ponderosa. p i n e and Douglas f i r were removed from a l l but a few r e l a t i v e l y i s o l a t e d o r i n a c c e s s i b l e a r e a s o f the r i d g e . V i r t u a l l y a l l o f the l a r g e Douglas f i r was at t h i s t i m e . cut Table IX shows the number o f stumps by s p e c i e s p r e s e n t a t the s i t e s selected for intensive examination.• Table X t r a c e s the h i s t o r y o f each s i t e as f a r back as possible. (ca. In most cases t h e n a t u r e o f t h e mature f o r e s t 2 0 0 y e a r s o l d ) can be determined from the stumps which have remained s i n c e the l o g g i n g o f the e a r l y 1 9 0 0 ' s . it Thus i s p o s s i b l e t o determine g e n e r a l l y the n a t u r e o f a. f o r e s t c o v e r which began t o d e v e l o p about 1700 A.D. Logging o f t h e mature, c l i m a x f o r e s t r e s u l t e d i n the regrowth o f a s t a n d o f s i m i l a r s p e c i e s c o m p o s i t i o n i n most cases.. Possibly a slight increase i n p r e c i p i t a t i o n over the l a s t few decades has r e s u l t e d i n an i n c r e a s e In the numbers o f young Douglas f i r i n stands which were mixed w i t h p i n e and f i r . In some c a s e s , r e c e n t l y c u t ponderosa p i n e stands which were not burned have become e s t a b l i s h e d t o Douglas f i r . The water t a b l e i n t h e a r e a may shown by the r i s i n g water a l s o r i s e as l e v e l o f A l k a l i Lake. S i n c e the c l i m a x montane f o r e s t c o n s i s t s o f an i n t e r g r a d e o f ponderosa p i n e and D o u g l a s . f i r , o c c u r r i n g i n mixed s t a n d s , o r o c c a s i o n a l l y i n pure stands of e i t h e r s p e c i e s , an i n c r e a s e i n m o i s t u r e might s h i f t t h e s p e c i e s , e s t a b l i s h m e n t p a t t e r n s i n f a v o u r o f 95 Douglas f i r . Ponderosa p i n e i s v e r y c l o s e t o i t s n o r t h e r n l i m i t i n the Southern Rocky Mountain Trench. F i r e i n t h e s e stands i s f o l l o w e d "by the e s t a b l i s h ment o f p i n e i n most c a s e s . to A more s e v e r e f i r e i s needed e l i m i n a t e the ponderosa p i n e due to i t s l o o s e , f i r e r e s i s t a n t b a r k , however a s u f f i c i e n t l y hot ground i n the c l i m a x p i n e f o r e s t may lodgepole pine. fire t r i g g e r an u n d e r s t o r y o f Dense s t a n d s o f l o d g e p o l e p i n e f r e q u e n t l y c o n t a i n young ponderosa p i n e and Douglas f i r t r e e s . Appar- e n t l y , i t t a k e s about 120 y e a r s on most s i t e s , w i t h o u t for fire, the lodgepole t o t h i n s u f f i c i e n t l y t o permit f i r or ponderosa p i n e t o become dominant. up t o l 8 0 y e a r s o l d may Lodgepole v e t e r n a s be found i n r e g e n e r a t i n g ponderosa p i n e and Douglas f i r s t a n d s , i n d i c a t i n g t h e e a r l i e r p r e s s u r e of f i r e a t the site. S e r a i g r a s s l a n d s may form a d l s c l i m a x f o r s e v e r a l decades on d r i e r s l o p e s f o l l o w i n g the removal o f t h e mature forest. The open t e r r a c e a r e a o f Premier Ridge f o l l o w e d this pattern. However, young Douglas f i r s have become e s t a - b l i s h e d i n m o i s t g u l l i e s and i n time w i l l r e i n v a d e t h e a r e a f o r m e r l y o c c u p i e d by t h e f o r e s t . F. S i t e H i s t o r y and t h e Paths of S u c c e s s i o n on Mountain Estella Logging has e x e r t e d o n l y a minor i n f l u e n c e on s o u t h and southwestern s l o p e s of E s t e l l a Mountain. the Cutting Table IX S t a t i s t i c s f o r stumps, Premier Ridge, Relict Agropyron No. stumps per acre No. stumps In macroplot No. D. F i r stumps 1969. Ponderosa Pine Young Middle Climax Poa-stlpa 13 139 9 22 9 9 . 9 0 3 32 2 5 2 2 2 0 32/14.7 2/N.A. *3/l4.7 Young Douglas F i r Middle Mature Purshla 4/15.2 2/18.5 2/N.A. 2/18.2 No. P. Pine stumps Lodgepole Pine 2/24.3 1/13.0 No. Larch stumps No. Lodgepole Pine stumps ON * Note: 3/14.7 numerator = no. stumps denominator = average diameter of stump 1" o f f ground In Inches. Table X F o r e s t cover o f Premier Ridge s i t e s , S i t e Name Previous R e l i c t bluebunchwheatgrass Open m a t u r e fir Bitterbrush Dense mature Dougla.s fir Clear cut & burned Shrub & s e r a i grassland Bluegrass-needlegrass Open c l i m a x fir Clear cut & burned Shrub & s e r a i grassland Young D o u g l a s f i r Semi-open c l i m a x Douglas f i r Selective Mid. Douglas f i r Open c l i m a x fir Selective logging 1920 to present Mature Probably fir Yg. Mid. Douglas f i r Ponderosa Ponderosa Pine Pine Climax Ponderosa Lodgepole Pine Pine Forest p a s t and p r e s e n t . Douglas Douglas Douglas Clear Bunchgrass 1920 1920 logging 1920 & 1965 N.A. Ponderosa Clear cut Cover sere None Ponderosa Burned 1931 Regen. D o u g l a s f i r & veterans Regen. D o u g l a s ( a l l ages) Dense M a t u r e fir 1920 Increase ppt. (?) A. Open c l i m a x Pine c u t & burned mature Serai grassland N. Present 1920 dense Open c l i m a x Pine Nature o f D i s t u r b a n c e f i r ^ Douglas Yg. P o n d e r o s a P i n e & Douglas f i r regen. Mature stand Pine . Ponderosa Open c l i m a x montane Dense L o d g e p o l e P i n e o l d Ponderosa Pine v e t e r a n s w i t h some Douglas f i r regen. forest & TABLE XI THE PATHS OF SUCCESSION ON PREMIER RIDGE SELECTIVE LOGGING MAINTAINS YOUNG TO MATURE STAND OF DOUGLAS FIR AND PONDEROSA PINE WITH SOME OLD VETERANS 100-200 YEAR CYCLE DEPENDING UPON ASPECT Climax Lodgepole pine forest Montane si Forest Open brush & serai grassland DISCLIMAX MAINTAINED BY SITE MOISTURE AND GRAZING PRESSURES Table X I I S t a t i s t i c s f o r stumps, E s t e l l a Mountain, . 1969 Serai Bluebunch Wheatgrass Serai Fescue No. stumps p e r a c r e 44 88 No.' stumps p e r s i t e 10 20 • Regen. Douglas F i r Larch 57 88 26 13 20 6 Lodgepole No. Douglas f i r stumps No. WB p i n e stumps 10/6.5 18/14.8 13/12.6 3/23.3 7/12.6 3/18.8 13/12.1 No. Lodgepole p i n e stumps No. L a r c h stumps Note: 1/16.1 numerator = No. stumps denominator = average d i a m e t e r i n i n c h e s 1 f o o t from ground level Table X I I I F o r e s t cover o f E s t e l l a . M o u n t a i n , past and p r e s e n t . S i t e Name Previous Forest Nature of D i s t u r b a n c e Present Regen. Douglas f i r Semi-open mature Douglas f i r Selective logging Semi-open mature Douglas f i r Dense L a r c h Selective logging L a r c h w i t h Douglas . fir understory Lodgepole P i n e Mature WB p i n e stand Burned 1931 Dense Lodgepole Pine forest S e r a i fescue Mature WB p i n e forest Burned 1 9 3 1 Serai grassland with WB p i n e s e e d l i n g s S e r a i bluebunch wheatgrass Mature WB p i n e forest Burned 1 9 3 1 Serai grassland with WB p i n e s e e d l i n g s Larch site. 1952 1952 Cover 101 has been c o n c e n t r a t e d on t h e more p r o d u c t i v e n o r t h and n o r t h western s l o p e s which a r e dominated by Englemann s p r u c e . south and southwestern s l o p e s a r e e s t a b l i s h e d t o Douglas f i r w i t h some s e r a i stands o f w e s t e r n a s p e c t s above 5*000 f e e t was of white-barked pine. was The larch. The a r e a on these p r e v i o u s l y covered by a f o r e s t The r e g e n e r a t i n g Douglas f i r s i t e s e l e c t i v e l y c u t about 1952 and i s c u r r e n t l y r e g e n e r a t i n g t o Douglas f i r . zone and was The l a r c h s i t e i s a l s o i n the Douglas f i r s e l e c t i v e l y cut about 1 9 5 2 . f a v o u r e d an x m d e r s t o r y o f Douglas f i r . T h i s t h i n n i n g has These t r e e s w i l l , d o u b t l e s s i n t i m e , e l i m i n a t e o r reduce the now larch. dominant S c a t t e r e d o l d ( l 8 0 y e a r s ) l o d g e p o l e p i n e s a t both o f t h e s e s u t e s suggest t h a t t h e y were p r o b a b l y burned over 200 y e a r s ago. The r e m a i n i n g t h r e e s i t e s on E s t e l l a Mountain were e s t a b l i s h e d on the burn o f 1931 which c o m p l e t e l y d e s t r o y e d the w h i t e - b a r k e d p i n e f o r e s t . The lodgepole pine s i t e i s r e p r e s e n t a t i v e o f the a r e a s which were r e f o r e s t e d s h o r t l y a f t e r the burn. Stumps o f any f o r e s t which might have e x i s t e d p r i o r t o t h e w h i t e - b a r k e d p i n e f o r e s t c o u l d not found. be N e i t h e r w h i t e - b a r k e d p i n e s e e d l i n g s nor the s e e d l i n g s o f any o t h e r c o n i f e r c o u l d be found under the dense stands of lodgepole p i n e . These s e e d l i n g s a r e , however, now be- coming e v i d e n t i n open a r e a s which were burned but f o r some TABLE XIV i THE PATH OF SUCCESSION ON ESTELLA MOUNTAIN (SW & S aspect) DOUGLAS FIR ZONE Larch o Lodgepole pine forest serai grassland DISCLIMAX ACCORDING TO SITE PPT (ASPECT) 100 YEAR MAXIMUM CYCLE 11 WHITE-BARKED PINE ZONE Mature White-bark pine Forest Lodgepole pine forest Serai grassland 80 YEAR MAY CYCLE DISCLIMAX DEPENDENT UPON SITE AND PPT. AND ASPECT 10.4 reason ( o f t e n a s p e c t ) have f a i l e d t o r e g e n e r a t e t o l o d g e pole pine. G. The P r o d u c t i v i t y o f t h e F o r e s t 1. Premier Ridge No attempt was made t o determine t h e t o t a l or n e t p r o d u c t i v i t y o f t h e f o r e s t . annual The methods r e q u i r e d t o measure n e e d l e f a l l , "branch growth and r o o t growth were beyond t h e scope o f t h i s i n v e s t i g a t i o n . For comparative e x a m i n a t i o n o f t h e s i t e s , t h e t o t a l volume o f t i m b e r was. determined i n each m a c r o p l o t and s u b s e q u e n t l y c o n v e r t e d t o acre u n i t s . The average a n n u a l increment was a l s o r e c o r d e d . These d a t a g i v e some i n d i c a t i o n o f t h e f o r e s t biomass w h i c h i s b e i n g m a i n t a i n e d a t each s i t e and t h e r a t e a t w h i c h i t i s increasing. Table XV l i s t s t h e f o r e s t p r o d u c t i v i t y d a t a f o r Premier R i d g e . The t o t a l volume o f t i m b e r i n c r e a s e s w i t h age, a p p a r e n t l y r e a c h i n g a peak i n t h e mature Douglas f i r s i t e which had 3,593 c u b i c f e e t o f stem wood. T h i s s i t e was b e g i n n i n g t o t h i n i t s e l f and t h e c e n t r e s o f many o f t h e l a r g e r t r e e s showed s i g n s o f r o t , r e d u c i n g t h e i r value. The ponderosa p i n e s i t e s c o n t a i n much l e s s t i m b e r volume than t h e c o r r e s p o n d i n g Douglas f i r s i t e s . ponderosa commercial The c l i m a x p i n e s i t e had a lower t i m b e r volume and a much lower a n n u a l increment pine s i t e s . (5.7 cu f t / a c ) than any o f t h e o t h e r In s p i t e of x e r i c nature of the s i t e , lodgepole t o wood p r o d u c t i o n , Premier R i d g e s i t e s . No. stems p e r a c r e 1 C •r-i PH .P-i xi •H 1 Climax P. c CD 1 u CD c CD Yg. P. Pj i Mid D. Fj Yg. D. Fj •u Mat. D. Fir CD ' Lodgepole P" Statistics relating 1 T a b l e XV 1930 605 331 958 261 s 74 3459 C h a r a c t e r i s t i c sta.nd age 22 55 95 80 100 280 65 F o r e s t canopy % 26 56 73 • 49 49 38 78 DBH a r e a p e r a c r e 4oo 91 161 130 109 74 701 Mean DBH a r e a .21 .15 .49 .15 .42 1.0 .20 T o t a l wood volume f t 3 1115 892 3593 919 1729 1573 l4li Annual increment* f t 3 50.5 16.5 37.5 11.3 16.6 5.7 21.3 a n n u a l increment = t o t a l wood volume ( f t 3 ) c h a r a c t e r i s t i c s t a n d age ( y r . ) . io6 p i n e stands showed a good a n n u a l increment 2. (21.3 cu f t / a c ) . E s t e l l a Mountain The p r o d u c t i v i t y d a t a f o r t h e t i m b e r o f t h e E s t e l l a Mountain s i t e s i s r e c o r d e d i n T a b l e X V I . The number o f stems per a c r e o f t h e E s t e l l a s i t e i s s i m i l a r t o t h o s e s i t e s o f c o r r e s p o n d i n g age on Premier R i d g e . Natural thinning of mature stands does n o t o c c u r and t h e s e o l d e r s t a n d s tend t o be more dense than t h e i r lower e l e v a t i o n c o u n t e r p a r t s . The volume o f t i m b e r on t h e young stands on E s t e l l a and P r e m i e r are comparable. The r e g e n e r a t i n g f i r s t a n d on E s t e l l a had a: volume o f 9 6 7 c u b i c f e e t o f wood w h i l e t h e young Douglas f i r s t a n d on Premier had a wood volume o f 1 , 1 1 5 c u b i c f e e t . At m a t u r i t y t h e D o u g l a s f i r and l a r c h f o r e s t s o f E s t e l l a - y i e l d volumes o f t i m b e r h i g h e r than t h e mature f i r stands on P r e m i e r , a l t h o u g h the "mature Douglas f i r " s i t e on t h e n o r t h e a s t s l o p e o f Premier produced a s u b s t a n t i a l volume o f timber (3,4-93 f t . ) due t o i t s m o i s t a s p e c t . The E s t e l l a f o r e s t grows more q u i c k l y than those of Premier R i d g e . At an age o f 35 y e a r s t h e y have s u r p a s s e d the t o t a l wood y i e l d s o f t h e lower e l e v a t i o n s . The a n n u a l increment o f t h e l o d g e p o l e p i n e s t a n d on E s t e l l a was 6 7 . 5 f t / y e a r , ' t h e h i g h e s t measured d u r i n g t h i s s t u d y . D i f f e r e n c e s i n s t o c k i n g d e n s i t y and s p e c i e s compos i t i o n o f t h e f o r e s t s made f u r t h e r comparison somewhat d i f f i cult. 107 Table XVI Statistics relating Mountain s i t e s . t o wood p r o d u c t i o n , E s t e l l a Regen. D. F i r No. stems p e r a c r e C h a r a c t e r i s t i c stand age F o r e s t canopy % • Larch 573 1633 25 125 Lodgepole P i n e 1254 35 35 72 71 126 266 170 .24 .21 .11 T o t a l DBH a r e a per acre Mean DBH a r e a T o t a l wood volume per acre (ft3) Annual increment* per a c r e * a n n u a l increment 967 _ = 38.3 3332 26.6 2365 67.5 t o t a l wood volume ( f t 3 ) c h a r a c t e r i s t i c s t a n d age ( y r . ) 108. H. Aggregate U n d e r s t o r y I. Premier Ridge The Productivity t o t a l annual understory p r o d u c t i v i t y i s p r e s e n t e d i n two forms; one, considering w i t h c h a r a c t e r i s t i c s t a n d age, r e l a t i o n s h i p with The and two, i t s relationship considering its f o r e s t canopy. e f f e c t o f c h a r a c t e r i s t i c s t a n d age u n d e r s t o r y p r o d u c t i v i t y i s shown i n F i g u r e 4 5 , on the including, f o r c o m p a r a t i v e p u r p o s e s , the p r o d u c t i o n o f the n a t u r a l • grassland. The p r o d u c t i v i t y o f the t h r e e open s e r a i s i t e s averages 7 1 . 7 gm/m 2 (638 l b / a c ) . component o f t h i s y i e l d . gm/m 2 (1,334 largest The p o t e n t i a l p r o d u c t i v i t y o f t h e s e areas (under a b e t t e r g r a z i n g 150 Grasses form the regime) i s p r o b a b l y about lb/ac). T o t a l p r o d u c t i v i t y i n c r e a s e s s l i g h t l y as f o r e s t r e g e n e r a t i o n commenced. T h i s r i s e was l a r g e L y c r e a s e s i n the b e a r b e r r y and due soapoiallie yields. t o InThe g r a s s component and the b i t t e r b r u s h components, w h i c h are used b y g r a z e r s , decreased s h a r p l y in yield. heavily The stands from 5 0 t o 100 y e a r s o f age show depressed t o t a l productivity r e a c h i n g o n l y 5 6 $ of the a g g r e g a t e p r o d u c t i o n o f the open s e r a i communities. production A l l components showed a d e c r e a s e i n and i n extreme cases a component o r s p e c i e s may a c t u a l l y disappear e n t i r e l y . Forbs may-be abundant on m o i s t 109 sites. As t h e f o r e s t matures and approaches the c l i m a x s t a t e , the t o t a l p r o d u c t i v i t y i n c r e a s e s l a r g e l y due natural thinning. The h e l i o p h y t e s reappear to and make s i g n i f i c a n t c o n t r i b u t i o n s t o i n c r e a s e the y i e l d . The f o r b s , b e a r b e r r y and b i t t e r b r u s h f r a c t i o n s a l l i n c r e a s e d markedly i n the c l i m a x f o r e s t . However, g r a s s p r o d u c t i o n i n the c l i m a x stand remains low, a c h i e v i n g o n l y 5 0 $ o f t h e y i e l d a t t a i n e d on the u n f o r e s t e d s i t e s . F i g u r e 44 shows the r e l a t i o n s h i p between u n d e r s t o r y p r o d u c t i v i t y and f o r e s t canopy. aggregate Under a canopy cover o f 2 o $ the p r o d u c t i v i t y i n c r e a s e s s l i g h t l y , due t o i n c r e a s e s i n y i e l d by b e a r b e r r y and soapoiallie. F o r e s t canopy v a l u e s g r e a t e r than 5 0 $ a r e a s s o c i a t e d with, a reduced p r o d i r t i v i t y o f the u n d e r s t o r y . P r o d u c t i o n under the h i g h e r f o r e s t canopy v a l u e s and 7 8 $ ) was communities. reduced (72$ t o 6 0 $ o f t h a t o f the n o n f o r e s t e d The g r a s s component d e c l i n e d s t e a d i l y as the f o r e s t canopy i n c r e a s e d . The 100$ Increase i n pro- d u c t i v i t y o f the open f o r e s t stands ( 2 6 $ and 3 8 $ canopy) i s due to an i n c r e a s e i n b e a r b e r r y . The a n n u a l increment o f the t i m b e r . a t each s i t e has not been i n c l u d e d i n F i g u r e 4 4 . Apparently bearing l i t t l e r e l a t i o n s h i p t o u n d e r s t o r y y i e l d s , the increment of timber d e c l i n e s r a t h e r s t e a d i l y , b e i n g h i g h e s t i n the young- CT I ro VJ1 o H O o 1 *|natural o i TO grassland 4 CD H* (-3 3 p~ CD I— 1 £ PJ fij CT o 4 CD CD CLCT P cr c t << CD ro o M} 03 o b CD £ W P *1 o •i (D ct H o 5 co o O ct • o cu o CL CD 4 r «<5 < 4 3 P CP. o o Ct O > S 0<< 4=r O Ul CQ O a C o ct 4 H* zarzi <! O f O Ct 3 IM OA o P cn CQ CD CQ o o cr co 4 oo Lx) 4 Ct Ct CD c 4 c cr CO si co 02 O o o P H I— h" CD 1 tri CD pj 4 0) 4 CD 3 i-d ct 4 CO CD „ B P p. 4 CD CD 4 O ft) 3* H- P D-, 4 CT P CD O Ct CD CD CO 4 N CD co o a on Figure 4 5 Figure 4 5 The a g g r e g a t e a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f P r e m i e r R i d g e a s i n f l u e n c e d b y c h a r a c t e r i s t i c s t a n d age Only major components a r e shown. The a g g r e g a t e a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f P r e m i e r R i d g e as Bitterbrush i n f l u e n c e d by c h a r a c t e r i s t i c stand age. Only major components a r c Dwarf Shrubs shown. ^ Soopolallie Forbs Grass Bearberry 150 100 gm/m" 5 0 n l l l i I 20 40 30 Characteristic Stand Age I 50 60 / •-3 O ct P w CQ cd ro. ct ct CD P cr CD • 'ri. rr CD 4 QJ H- P CD •D cr CA H- P o cn 13- cr •-3 Q P P cr i—i CD cn J>d <j rr H H cr .i-3 tr ro CO i o i i H o —«3 o Skookumchuck Prairie P 09 >s CD 09, 00 o^ 0> oo CO OO Ul R e l i c t Agropyron oo H UJ O ct ro P 4=" 4=" OO CO 4^ -<1 4=- ro o oo H P Purshia P Ul 03 4=r o ui o oo Poa-stipa ro co ct co O << Ul I— 1 t- 1 ui ro ro 00 ro o-> ui M o ON ui CT\ H oo ui 4=- vo H Yg. D. P i r <n 4 o aMid D. F i r d o ct H» <J HCt oo oo H H 1 Ul i~3 i-3 ro H ^o o\ 1-3 ro ro 4=- 4=- vo ro o H Lodgepole Yg.. P. P i n e ^ O ro 3 ro ro ro Ul ro o Ul ro CT\ 4^OO vo Mat. D. F i r oo oq ro M O^ O H Ul H> o vo oo o 0^ ro OO i— 1 4=- 4=- O H Mid P. P i n e 00 ro ui SIT Climax CD 1 : L 3 est s t a n d and l o w e s t i n t h e o l d e s t . t r e n d i s t h e mature Douglas One d e v i a t i o n from t h i s f i r (age 95 y e a r s ) which i s l o c a t e d on the m o i s t n o r t h e a s t s l o p e and would consequently be expected t o grow more r a p i d l y . 2. E s t e l l a Mountain The net a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a Mountain f o l l o w s a p a t t e r n s i m i l a r t o t h a t found on Premier Ridge. Open a r e a s g e n e r a l l y produce h i g h y i e l d s , o f h e r b - aceous s p e c i e s , w h i l e the f o r e s t s i t e y i e l d s tend t o be reduced p r i n c i p a l l y i n t h e g r a s s component. y i e l d o f herbaceous The i n c r e a s e d s p e c i e s n o t e d i n young r e g e n e r a t i n g stands on P r e m i e r Ridge, was r e p e a t e d on E s t e l l a . However, a l l o f t h e i n c r e a s e d p r o d u c t i v i t y a t t h e 25 y e a r o l d s i t e r e s u l t e d from b e a r b e r r y . The dwarf shrub component was s h a r p l y reduced a t o l d s i t e s w i t h h i g h f o r e s t canopy values. The e f f e c t o f t h e f o r e s t canopy on t h e u n d e r s t o r y p r o d u c t i v i t y i s shown i n F i g u r e 4 7 . The n e t u n d e r s t o r y p r o d u c t i v i t y d e c l i n e s as f o r e s t r e g e n e r a t i o n commences. The i n c r e a s e i n y i e l d a t 3 5 $ c o v e r i s e n t i r e l y due t o b e a r berry. The dense stands y i e l d o n l y 4 7 $ as much per annum as do the open s i t e s . The g r e a t e s t r e d u c t i o n s o c c u r i n t h e g r a s s and shrub components. F i g u r e 4 7 does not i n c l u d e t h e a n n u a l o f the t i m b e r a t each s i t e . increment The h i g h e s t a n n u a l t i m b e r increment observed i n the study was found a t t h e r a p i d l y F i g u r e 46. The a g g r e g a t e a n n u a l u n d e r s t o r y p r o d u c t i v i t y E s t e l l a Mountain as i n f l u e n c e d by c h a r a c t e r i s t i c s t a n d age. Only major components a r e i n c l u d e d . of | | Bearberry Soapolallie Dwarf Shrubs jgjggl Forbs ywA Grass 200 H 150 gm/m c 100 50 I 0 • I 25 T" 50 T I 75 Characteristic 100 Stand Age 1 125 1 150 Figure 47 The a g g r e g a t e a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a M o u n t a i n i n f l u e n c e d by f o r e s t canopy. O n l y m a j o r c o m p o n e n t s a r e shown. Figure 47. The a g g r e g a t e a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a Mountain as i n f l u e n c e d by f o r e s t canopy. Only major c o m p o n e n t s a r e shown. ml m mi • • 200 as Grasses Forbs Dwarf Shrubs Soapoiallie Bearberry H 150 H gm/m £ 100 50 J 1 J 0 10 T" 20 30 40 F o r e s t Canopy % 5 0 60 80 Table XVIII The aggregate a n n u a l u n d e r s t o r y p r o d u c t i v i t y o f E s t e l l a Mountain SITE NAME Serai Fescue Serai Bluebunch . Wheatgrass Regen. D. F i r Lodgepole Larch Grass 75 31 40 15 34 Forb 24 15 15 "ll 5 Dwarf shrub 3 11 6 12 2 Soapolallie 17.4 T Bearberry 14 - Total Wt. in 133.4 gm/m' 57 9.0 114 184.0 4.6 2.5 1.0 2 43.6 45.5 117 growing l o d g e p o l e p i n e s i t e (age 35 y e a r s ) . The older s i t e s show a r e d u c t i o n i n p r o d u c t i o n , but remain h i g h e r t h a n the r a t e o f p r o d u c t i o n observed on Premier Ridge. 118 rv DISCUSSION The v e g e t a t i o n p a t t e r n s o f the t r e n c h f l o o r r e f l e c t the p r e v i o u s i n f l u e n c e s o f man. The l o g g i n g o f t h e e a r l y 1 9 0 0 ' s and t h e f i r e s o f t h e 1 9 3 0 ' s have l e f t a p a t c h work o f f o r e s t and open areas o f v a r y i n g s t a g e s o f t h e succession. These areas a r e i n a s t a t e o f dynamic p r o - g r e s s i o n ; most o f t h e a r e a i s p o t e n t i a l f o r e s t and i t i s t h i s d i r e c t i o n t h a t t h e p r o g r e s s i o n o r s u c c e s s i o n i s moving. C a t t l e and w i l d u n g u l a t e s p r e v i o u s l y r e s t r i c t e d i n t h e a r e a , a r e c u r r e n t l y e x p l o i t i n g these u n f o r e s t e d s e r a i rangelands. The p r e v i o u s e x i s t a n c e o f f o r e s t s on these l a n d s i s s t r o n g l y evidenced by the stumps which have remained i n t a c t , photo- graphs and t h e r e c o r d s o f f i r e and l o g g i n g o f t h e a r e a . ': S i m i l a r records e x i s t f o r the east w a l l of the t r e n c h . The most n o t i c e a b l e e f f e c t o f t h e regrowth o f the f o r e s t on areas which f o r some twnty t o f o r t y y e a r s have remained w i t h o u t t r e e s , i s a r e d u c t i o n i n t h e p r o d u c t i v i t y o f t h e u n d e r s t o r y community upon w h i c h t h e g r a z e r s l a r g e l y depend. The p a t t e r n o f r e g e n e r a t i o n has been one i n which the more m o i s t a s p e c t s , such as t h e n o r t h e a s t and e a s t s l o p e s , stream channels and s m a l l draws have been first. invaded Thus t h e t r e e s tend t o c i r c u m s c r i b e areas then c l o s e i n the r e m a i n i n g spaces. T h i s i n v a s i o n has proceeded so g r a d u a l l y t h a t i t f r e q u e n t l y goes u n n o t i c e d . 119 D i v e r s i t y i n c l i m a t e , v e g e t a t i o n and soil p r e v e n t e d the use of a system f o r randomly l o c a t i n g sites f o r i n t e n s i v e study. The s i t e s were c a r e f u l l y s e l e c t e d a f t e r g e n e r a l study. D u p l i c a t i o n o f t h e e x c l o s u r e s was not p o s s i b l e due t o the c o s t r e q u i r e d f o r t h e i r c o n s t r u c t i o n . 1. The Premier Ridge Area The removal o f t h e mature montane f o r e s t Premier Ridge between 1910 and from 1 9 2 0 , and the subsequent f o r e s t f i r e s l e d t o the e s t a b l i s h m e n t o f communities w i t h out t r e e s on v a r i o u s p a r t s o f the r i d g e w h i l e on o t h e r p a r t s r e g e n e r a t i o n o f f o r e s t commenced almost i m m e d i a t e l y . The f l o r i s t i c c o m p o s i t i o n o f the u n f o r e s t e d s e r a i communities has been a l t e r e d by g r a z i n g i n many r e g i o n s . r e l i c t Agropyron stock. However, the s i t e has r e c e i v e d l i t t l e g r a z i n g by domestic At p r e s e n t , 40 y e a r s a f t e r the l a s t major f i r e s i x t y y e a r s a.fter l o g g i n g , t h i s s i t e had developed of bluebunch and a cover wheatgrass ( 5 0 $ ) and j u n e g r a s s ( 9 $ ) . Few o t h e r g r a s s s p e c i e s and v e r y few f o r b s a r e p r e s e n t a t the site. Under p r o l o n g e d p r o t e c t i o n from g r a z i n g and without the i n v a s i o n o f t r e e s , t h i s s i t e i s b e g i n n i n g t o t a k e on the c h a r a c t e r i s t i c s o f a. n a t u r a l g r a s s l a n d s i m i l a r i n n a t u r e t o the Skookumchuck P r a i r i e . Since t h i s i s p o t e n t i a l l y forest l a n d , the A g r o p y r o n - K o e l e r i a community might be i n t h i s termed as d i s c l i m a x . On the a d j a c e n t u n f o r e s t e d l a n d s case 120 communities o f Poa spp. and S t i p a spp. a r e common. The i n i t i a t i o n o f f o r e s t growth on these s i t e s has a pronounced a f f e c t on t h e f l o r i s t i c s o f t h e g r a s s y s e r a . wheatgrass, Bluebunch Kentucky b l u e g r a s s and Canada b l u e g r a s s d i s a p p e a r r a p i d l y ; rough f e s c u e and j u n e g r a s s may l i n g e r on i n t h e f o r e s t e d s i t e s b u t d i s a p p e a r as t h e canopy exceeds 6 0 $ . P i n e g r a s s , u s u a l l y o n l y an o c c a s i o n a l o r r a r e s p e c i e s i n the u n f o r e s t e d community, i n c r e a s e s r a p i d l y as t h e f o r e s t r e g e n e r a t e s , f o r m i n g t h e o n l y g r a s s p r e s e n t under v e r y dense f o r e s t c a n o p i e s . To t h e c a s u a l o b s e r v e r , t h e r e l a t i v e change i n abundance o f g r a s s s p e c i e s as t h e f o r e s t develops i n t h e f o r e s t e d s i t e s may go u n n o t i c e d . Forbs were v a r i a b l e i n abundance throughout t h e s u c c e s s i o n ; as w i t h g r a s s e s , h e l i o p h y t e s predominated on the u n f o r e s t e d a r e a s but g r a d u a l l y g i v e way t o t h e s c i o p h y t e s as t h e f o r e s t developed. The more h e a v i l y g r a z e d . u n f o r e s t e d s i t e s had many more s p e c i e s (22) than d i d t h e l i g h t l y g r a z e d open a r e a s (5). The shrubs were most abundant on t h e un- f o r e s t e d a r e a s and e a r l y i n t h e f o r e s t s e r e s ; as f o r e s t canopy r e a d i n g s exceeded 5 0 $ shrub abundance d e c l i n e d . b r u s h was noted t o be v e r y i n t o l e r a n t . Bitter- On t h e o t h e r hand, s o a p o i a l l i e was more abundant I n t h e t i m b e r e d a r e a s , o f t e n e x i s t i n g under major b r e a k s i n t h e f o r e s t canopy. Bear- b e r r y was most common on t h e open communtles, b u t was common 121 In t h e v e r y young stages o f f o r e s t r e g e n e r a t i o n ; i t d e c l i n e d a g a i n under v e r y dense f o r e s t c a n o p i e s . The p r o d u c t i v i t y o f t h e communities o f t h e unf o r e s t e d areas was g e n e r a l l y depressed by previous g r a z i n g . P r o b a b l y few s i t e s were p r o d u c i n g n e a r optimum l 8 0 gm/m 2 (1,600 l b / a c . ) o f which t h e s e fenced s i t e s a r e c a p a b l e . r e l i c t Agropyron community produced 6 5 gm/m 2 The (579 lb/ac.) o f g r a s s ; t h i s y i e l d appeared t o drop t o 3 4 gm/m 2 (307 lb/ac.) as f o r e s t r e g e n e r a t i o n began and c o n t i n u e d t o d e c l i n e , r e a c h i n g a low o f 12 gm/m 2 (107 l b / a c ) . Production i n the climax f o r e s t appeared t o r i s e t o 25 gm/m , a l t h o u g h t h i s 2 quantifi- c a t i o n o f t h e d e c l i n e i s approximate and a l t h o u g h i t may be m o d i f i e d b y changes i n f l o r i s t i c composition. The p r o d u c t i v i t y o f t h e f o r b s i s seemingly affected i n the general pattern o f the succession. n o t a b l e e x c e p t i o n was i n t h e c l i m a x ponderosa p i n e little The o n l y stand where f o r b p r o d u c t i o n was h i g h e s t ( 4 0 gm/m 356 l b / a c ) . 2 In s p i t e o f t h e r e l a t i v e l y low y i e l d o f f o r b s when compared t o g r a s s e s , they a r e u n d o u b t e d l y used b y mule deer and w h i t e t a i l e d deer e a r l y i n t h e s p r i n g as t h e g r a s s i n i t i a t e s growth. The y i e l d b y b e a r b e r r y was h i g h e s t under open f o r e s t where canopies range from 2 0 $ t o 4 0 $ ; on these s i t e s t h e y i e l d was about 6 0 gm/m 2 (534 l b / a c ) . Bitterbrush production (annual t w i g s o f l e a f and wood) was h i g h e s t i n t h e u n f o r e s t e d s i t e s and d e c l i n e r a p i d l y 122 as f o r e s t r e g e r n a t i o n began. yielded 6.3, 14.1 9 . 0 gm/m 2 (80 l b / a c ) . 2 sites and 4 . 8 gm/m w i t h an average o f 8 . 4 gm/m (75 l b / a c . ) o f b i t t e r b r u s h . was The t h r e e u n f o r e s t e d 2 The p r o d u c t i o n i n c l i m a x P r o d u c t i o n on the o t h e r s i t e s d i d not exceed 2 . 5 gm/m 2 (22 l b / a c . ) forest forested Bitterbrush i s h e a v i l y used on the u n f o r e s t e d a r e a s o f the r i d g e and protects (from g r a z i n g ) many o f the g r a s s e s w h i c h d e v e l o p under i t s canopy. grass On the h e a v i l y g r a z e d productivity s i t e s most o f the i s r e a l i z e d under the b i t t e r b r u s h p l a n t s where i t i s not a v a i l a b l e t o g r a z e r s . • • , S o a p o i a l l i e p r o d u c t i o n on the t h r e e u n f o r e s t e d averaged 5 . 2 gm/m 2 (46 l b / a c . ) and reached i t s h i g h e s t i n the e a r l y s t a g e s o f f o r e s t r e g e n e r a t i o n , 3 0 gm/m 2 sites yield (267 lb/ac). As the s u c c e s s i o n proceeded beyond t h i s stage p r o d u c t i o n o f s o a p o i a l l i e d i d not exceed 2 . 5 gm/m (22 2 The f o r e s t stands selected lb/ac) f o r s t u d y on Premier Ridge i n c l u d e d Douglas f i r ( 3 ) * ponderosa p i n e ( 3 ) and lodgepole pine corresponding ( l ) . The number o f stems per a c r e f o r each age o f t h e s u c c e s s i o n was h i g h e s t f o r lodge- p o l e p i n e , f o l l o w e d b y Douglas f i r . lowest number o f s t e m s per a c r e . Ponderosa p i n e had The a n n u a l Increment o f wood p r o d u c t i o n f o r t h e f o r e s t s i t e s v a r i e d from 5 0 . 5 f t ^ / year i n the young Douglas f i r stand t o 5 - 7 f t , 3 / y e a r i n the forest. the ' climax The t i m b e r volume per a c r e ranged from 8 9 2 f t - 3 t o 123 to 1,729 f t ^ on the west s i d e o f the r i d g e . The o n l y mature Douglss f i r s i t e which c o u l d be found was on the n o r t h e a s t s i d e o f the r i d g e . I t s t o t a l volume was age o f 9 5 y e a r s the a n n u a l increment f t 3 and a t an 3,593 o f t h i s s t a n d was 3 7 . 5 f t 3 / y e a r , r a t h e r h i g h when compared t o the west s i d e f o r e s t s o f s i m i l a r age. W h i l e the south and w e s t e r n aspects a r e not s u i t e d t o the r a p i d p r o d u c t i o n o f t i m b e r , the n o r t h and east s l o p e s grow t r e e s q u i c k l y . T h i s f a c t may be u s e f u l i n the f o r m u l a t i o n o f i n t e g r a t e d l a n d use p o l i c i e s f o r such areas. The n e t u n d e r s t o r y p r o d u c t i v i t y o f t h e u n f o r e s t e d s i t e s averaged 7 5 gm/m 2 to l45 gm/m 2 (1,291 (839 l b / a c ) . This value increased l b / a c ) a s f o r e s t r e g e n e r a t i o n commenced. In o l d e r stands the net u n d e r s t o r y p r o d u c t i v i t y t o l e s s than 40 gm/m 2 (356 l b / a c ) . decreased As these stands reach m a t u r i t y and n a t u r a l t h i n n i n g o c c u r s , a g r a d u a l i n c r e a s e i n net u n d e r s t o r y p r o d u c t i v i t y o c c u r s . The c l i m a x stand o f ponderosa p i n e exceeded the n e t p r o d u c t i v i t y o f any s i t e y i e l d e d 147 gm/m 2 (1,308 other l b / a c ) . However i t i s Important t o r e c a l l t h a t the most v a l u a b l e component t o the g r a z i n g animal (the g r a s s e s , f o r b s and b i t t e r b r u s h ) a l l decrease markedly as r e g e n e r a t i o n o f the f o r e s t b e g i n s . The Increases i n y i e l d are l a r g e l y a t t r i b u t a b l e to bearberry s o a p o i a l l i e w h i c h exxjerience l i t t l e g r a z i n g . and Furthermore the 124 g r a s s o f t h e f o r e s t e d s i t e s i s p i n e g r a s s which has l i t t l e or no n u t r i t i o n a l v a l u e as a w i n t e r f o r a g e and f r e q u e n t l y i s n o t a v a i l a b l e beyond September o r l a t e August when i t s n u t r i t i o n a l v a l u e drops r a p i d l y and i s beaten down by f a l l r a i n s and snow storms. 2. The E s t e l l a Mountain Area The E s t e l l a s i t e s have n o t been g r a z e d by domestic stock. The two major f a c t o r s g o v e r n i n g t h e i r p r e s e n t sturcture were t h e s e l e c t i v e l o g g i n g about 1 9 5 2 and t h e f i r e s o f 1 9 3 4 . The e f f e c t o f e l e v a t i o n i s a prime i n h e r e n t h a b i t a t f a c t o r for the E s t e l l a sites. The f l o r i s t i c s o f t h e u n f o r e s t e d a r e a s o f E s t e l l a Mountain a r e n o t d i s s i m i l a r t o those o f t h e Premier area. Ridge Bluebunch wheatgrass o r rough f e s c u e u s u a l l y domin- a t e t h e community; s e v e r a l o t h e r g r a s s e s were i n some e v i dence. At t h e 5,900 was rough f e s c u e ; a t f o o t e l e v a t i o n , t h e dominant bunchgrass 6,200 f e e t . i t was wheatgrass. At t h i s l a t t e r e l e v a t i o n the abundance o f the herbaceous c o v e r was d i s t i n c t l y l e s s than t h a t a t 5,900 feet. P i n e g r a s s was p r e s e n t in. the u n f o r e s t e d communities i n small, amounts (5$ c o v e r ) but I n c r e a s e d ( 3 5 $ c o v e r ) as f o r e s t r e g e n e r a t i o n began. and Rough f e s c u e and wheatgrass became markedly e v e n t u a l l y d i s a p p e a r e d as t h e f o r e s t canopy reduced developed.. P i n e g r a s s i s t h e most e v i d e n t g r a s s s p e c i e s p r e s e n t i n dense s t a n d o f t r e e s . 125 Forbs w e r e g e n e r a l l y abundant a t a l l s i t e s on E s t e l l a and no t r e n d s i n abundance were d i s c e r n a b l e . How- e v e r , g i v e n t i m e , t h e b u n c h r a s s community below feet may develop 6,000 as a d i s c l i m a x community s i m i l a r t o some on Premier Ridge; i n the s e r e s t o f o l l o w f o r b s may be reduced i n the u n f o r e s t e d communities. T h i s i s u n l i k e l y , however, as t r e e r e g e n e r a t i o n may o c c u r on t h e s e s i t e s before s u f f i c i e n t time has passed t o e s t a b l i s h a " g r a s s l a n d " d i s c l i m a x community. The shrubs on E s t e l l a showed no major trends w i t h regard t o the s u c c e s s i o n . S o a p o i a l l i e was found i n the dense stands o f l o d g e p o l e p i n e where i t e x i s t s p r i m a r i l y under gaps i n the o v e r s t o r y canopy. P r o d \ A c t l v i t y o f the g r a s s e s on the u n f o r e s t e d was s i m i l a r t o t h a t on P r e m i e r Ridge. y i e l d was 7 5 gm/m 5,900 f e e t the ( 6 6 8 l b / a c . ) but had dropped t o 3 1 gm/m 2 (262 At sites 2 lb/ac.) a t 6,200 feet. The y i e l d o f g r a s s e s d e c l i n e d r a p i d l y as f o r e s t r e g e n e r a t i o n o c c u r s . Thirtyfive years a f t e r r e g e n e r a t i o n began, the p r o d u c t i v i t y o f the g r a s s component was 15 gm/m 2 (13^ l b / a c . ) . This r a p i d d e c l i n e i s due t o t h e v e r y r a p i d growth o f the t r e e s once they came e s t a b l i s h e d . be- At these e l e v a t i o n s p r e c i p i t a t i o n i s a f f e c t i v e throughout t h e summer and thus t h e growing p e r i o d I s extended i n t o summer beyond t h a t found a t the v a l l e y bottom e l e v a t i o n s where growth I s c u r t a i l e d by mid Forb p r o d u c t i v i t y d e c l i n e s as t h e s u c c e s s i o n July. progresses, 126 b e i n g h i g h e s t on t h e u n f o r e s t e d s i t e s , 24 and 15 gm/m 2 a v e r a g i n g 15 gm/m 2 the h i g h f o r e s t ( 1 3 5 l b / a c . ) and changed l i t t l e canopy v a l u e s , 15 gm/m 2 under (125 l b / a c ) . Dwarf shrubs a l s o d e c l i n e s t e a d i l y as t h e s u c c e s s i o n p r o c e e d s . B e a r b e r r y y i e l d s were h i g h e s t i n t h e m i d d l e f o r e s t range, sometimes as h i g h as Soapolallie 120 gm/m produced v e r y l i t t l e the u n f o r e s t e d a r e a s . canopy d e v e l o p e d . 2 (1,068 ( 1 7 gm/m 2 canopy lb.ac). ( 1 5 1 l b / a c . ) on The y i e l d I n c r e a s e d as t h e f o r e s t Representative y i e l d s f o r the timbered a r e a s were about 4 5 gm/m 2 (401 l b / a c ) . The t i m b e r p r o d u c t i o n on E s t e l l a was, as might be expected from p r e c i p i t a t i o n e f f e c t i v e n e s s d a t a , much b e t t e r than t h e p r o d u c t i o n reached on P r e m i e r R i d g e . The two s e l e c t i v e l y logged s i t e s had a,n a n n u a l increment o f 38 f t 3 and 27 f t , 3 . The young l o d g e p o l e s i t e has an annua1 growth r a t e o f 6 8 f t 3 o f t i m b e r p e r y e a r p e r a c r e . The d i f f e r e n c e between P r e m i e r Ridge and E s t e l l a Mountain ca.n l a r g e l y be a t t r i b u t e d t o the increased of the l a t t e r and t h e consequences of effect o f microclimate. The i n c r e a s e d summer r a i n f a l l , extends t h e growing elevation season a.nd a l t h o u g h t h e t e m p e r a t u r e s a r e l o w e r , t h e a v a i l a b l e and e f f e c t i v e m o i s t u r e i s much g r e a t e r than i t i s f o r Premier Ridge. The n e t pr o d u c t i v i t y o f t h e u n d e r s t o r y on E s t e l l a 127 g e n e r a l l y d e c l i n e s as t h e s u c c e s s i o n p r o g r e s s e s . An i n - c r e a s e i n y i e l d i s n o t e d i n t h e youngest stage o f t h e r e generation cycle studied. T h i s i n c r e a s e was e n t i r e l y due to a h i g h y i e l d h y b e a r b e r r y . Those components which may b considered u s e f u l to n a t i v e ungulates, the grasses, forbs and dwarf s h r u b s , g e n e r a l l y d e c l i n e i n y i e l d as t h e f o r e s t r e g e n e r a t i o n proceeds. W h i l e g r a s s p r o d u c t i o n may be moderate under some f o r e s t s t a n d s , t h e s p e c i e s c o m p o s i t i o n (mainly pinegrass) i s not s u i t e d to w i n t e r i n g ungulates. Trad i t lona], l y , s t u d i e s which have compared t h e e f f e c t o f t h e f o r e s t on u n d e r s t o r y p r o d u c t i v i t y , have e l i m i n a t e d t h e s u c c e s s i o n a l element i n an attempt t o remove as many v a r i a b l e s as p o s s i b l e . Pase (1958) com- pared t h e herbage p r o d u c t i o n and s p e c i e s c o m p o s i t i o n under immature ponderosa p i n e i n t h e B l a c k H i l l s . Stand age was h e l d c o n s t a n t , b u t a r t i f i c i a l t h i n n i n g had produced stands v a r y i n g i n f o r e s t canopy from 0 $ t o 7 1 $ and w i t h a base a r e a from 0 t o 215 f t p e r a c r e . 2 Pase ( i b i d ) found t h a t g r a s s p r o d u c t i o n on open ( u n f o r e s t e d ) a r e a s was 7 4 times g r e a t e r than wa.s produced i n stands which had a b a s a l a r e a o f 215 f t p e r a c r e . Forbs and shrubs were a l s o 2 i n t o l e r a n t t o i n c r e a s e d f o r e s t canopy, p r o d u c i n g l e s s than 50 l b / a c . o f a i r - d r i e d f o r a g e under a canopy o f 7 1 $ . Halls and S c h u s t e r ( 1 9 ^ 5 ) s t u d i e d herbage p r o d u c t i o n i n p i n e - 128 hardwood f o r e s t s i n Texas, measured herbage, f o r e s t cover p e r c e n t and t r e e b a s a l a r e a b u t made no mention o f t h e age o f t h e stands o r t h e i r s u c c e s s i o n a l s t a t u s . . D e s p i t e a c o n s i d e r a b l e volume o f l i t e r a t u r e , t h e concept o f a b a l a n c e between t h e f o r e s t and i t s u n d e r s t o r y has n o t been c l o s e l y examined. Individual investigation ( u s u a l l y proponents o f one t h e o r y ) have r e p o r t e d t h e r e s u l t s o f experiments d e s i g n e d t o show t h a t e i t h e r light or r a i n f a l l l i m i t understory p r o d u c t i v i t y conversely, Barrett (1965). B a r r e t t and Youngberg (1965) have shown t h a t a heavy u n d e r s t o r y i n h i b i t s o r m i n i m i z e s wood p r o duction. McConnell and Smith (1970) reported that thinning dense (2,800 stem/ac.) stands o f ponderosa p i n e r e s u l t e d i n dramatic increases i n understory p r o d u c t i v i t y eight years f o l l o w i n g the t h i n n i n g . These r e s u l t s suggest that there may be a c t i v e c o m p e t i t i o n f o r some m a t e r i a l , p o s s i b l y water o r n u t r i e n t s , between t h e f o r e s t and t h e u n d e r s t o r y . In a d d i t i o n t o t h e annual y i e l d o f a. p i e c e o f l a n d t h e r e i.s a l s o a. "maintenance c o s t " which must be c o n s i d e r e d . This c o u l d be r e c o g n i z e d as t h e energy r e q u i r e d t o m a i n t a i n t h e p l a n t biomass a l i v e d u r i n g t h e y e a r . On t h e u n f o r e s t e d a r e a s t h e t o t a l p r o d u c t i v i t y i s c h a n n e l l e d i n t o t h e p r o d u c t i o n o f g r a s s e s , f o r b s and shrubs; t h e l a r g e s t p a r t o f which i s . a v a i l a b l e t o g r a z e r s . 129 As f o r e s t r e g e n e r a t i o n commences and t h e t i m b e r matures, more and more o f the n u t r i e n t s a r e taken up by the f o r e s t t o form the new growth and t o m a i n t a i n the e x i s t i n g volume of l i v i n g t i s s u e . Hence t h e r e a r e l e s s n u t r i e n t s freely a v a i l a b l e t o the u n d e r s t o r y community.' Grasses and f o r b s : do not expend much energy m a i n t a i n i n g the p r e v i o u s y e a r ' s growth above the ground s u r f a c e . Shrubs,•• h o w e v e r d o r e - q u i r e some energy t o m a i n t a i n t h e t i s s u e s developed previous years. in The volume o f t h i s t i s s u e , on a u n i t a r e a b a s i s , i s much l e s s than f o r t r e e s . As v e g e t a t i o n p r o g r e s s e s from open r a n g e l a n d t o timbered range, each s u c c e e d i n g y e a r sees more and more energy and n u t r i e n t s t i e d up i n t h e maintenance and o f the t r e e s . growth I r r e s p e c t i v e o f the e f f e c t s o f the f o r e s t canopy on the u n d e r s t o r y i t i s not s u r p r i s i n g t h a t unders t o r y p r o d u c t i v i t y decreases as the biomass o f the t r e e s increases. There i s no q u e s t i o n t h a t as a s u c c e s s i o n p r o g r e s s e s from u n f o r e s t e d t o f o r e s t e d l a n d , a d r a m a t i c c r e a s e i n the xanderstory t a k e s p l a c e . d e c l i n e i s most apparent Furthermore, dethis i n t h a t p a r t o f t h e community which i s g e n e r a l l y r e c o g n i z e d t o be o f most b e n e f i t t o g r a z i n g animals. A l l but a few o f the c r i t i c a l w i l d l i f e w i n t e r ranges which o c c u r on the f l o o r of the s o u t h e r n Rocky 130 Mountain Trench a r e p o t e n t i a l l y f o r e s t . Tree r e g e n e r a t i o n has begun on a l l o f t h e s e a r e a s and i s w e l l underway on Premier Ridge. As t h e open u n f o r e s t e d range acreage s h r i n k s a n n u a l l y , t h e g r a z i n g p r e s s u r e on t h e r e m a i n i n g open a r e a s becomes more i n t e n s e . Many communities, particularly those n e a r water and on l e s s steep t e r r a i n a r e a l r e a d y o v e r grazed. There i s a v a l u e t o t h e t i m b e r which w i l l develop on many a r e a s , p a r t i c u l a r l y t h e n o r t h and n o r t h e a s t s l o p e s . The p e r i o d between c u t s on t h e south and s o u t h w e s t e r n i s about 200 y e a r s . aspects The economic v a l u e o f such a h a r v e s t i s p r o b a b l y v e r y s m a l l when c o n s i d e r e d on an a n n u a l b a s i s . If f o r e s t r e g e n e r a t e s on t h e c r i t i c a l s l o p e s , t h e o p t i o n o f w i l d l i f e t o use t h e v a s t a l p i n e summer ranges of i n the heart t h e Rocky Mountains ( l a r g e l y untouched by man a t p r e s e n t ) w i l l be l o s t . T h i s would g r e a t l y decrease t h e " u s e f u l " p r o d u c t i v i t y o f these a l p i n e a r e a s from t h e s t a n d p o i n t o f human b e n e f i t , t o b o t h consumptive and non-consumptive u s e r s of the resource. In a d d i t i o n , I f regeneration continues, s u b s t a n t i a l summer ranges f o r c a t t l e w i l l be l o s t and m a r g i n a l ranches o f the a r e a w i l l be u n a b l e t o r e p l a c e t h e s e g r a z i n g a r e a s i n a v a l l e y where i n d u s t r y and human p o p u l a t i o n a r e increasing rapidly. 131 REFERENCES CITED A n d e r s o n , R. C , 0 . L. L o u c k s and A. M. S w a i n . 1 9 6 9 . Herba c e o u s r e s p o n s e t o c a n o p y c o v e r , l i g h t i n t e n s i t y , and t h r o u g h f a l l p r e c i p i t a t i o n In c o n i f e r o u s f o r e s t s . Ecology. 5 0 ( 2 ) : 2 5 5 - 2 6 3 . A r n o l d , J . F. 1 9 5 0 . 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Combined v a r i a b l e e q u a t i o n s and v o l u m e - b a s a l a r e a r a t i o s f o r t o t a l c u b i c f o o t volumes o f t h e commercial t r e e s o f B. C. F o r . Chron. 40(2) :258-26l. Stokes,, M. A. and T. L. S m i l e y . 1 9 6 8 . An i n t r o d u c t i o n t o t r e e r i n g d a t i n g . C h i c a g o , U n i v . o f Chicago P r e s s 1-73- W e s t l a k e . D. G. 1 9 6 3 . Comparisons o f p l a n t p r o d u c t i v i t y . B i o l . Rev. 3 8 ( 2 ) . - 3 8 5 - 4 2 5 . 133 Young; J . A., J . A. B. McArthur and D. W. H e d r i c k . 1 9 6 7 . Forage u t i l i z a t i o n i n a m i x e d - c o n i f e r o u s f o r e s t o f n o r t h e a s t e r n Oregon. J . F o r e s t r y 3 5 : 3 9 1 - 3 9 3 . • 134 APPENDIX I The p h y s i c a l c h a r a c t e r i s t i c s o f t h e s i t e s on P r e m i e r Ridge and E s t e l l a M o u n t a i n . Premier Ridge S i t e Name Aspect % Slope E l e v a t i o n I n Feet Skookumchuck P r a i r i e Nil 0 2,610 R e l i c t Bunchgrass 260° 43 3,475 260° 31 3,150 Poa - S t i p a 270° 30 2,920 Young Douglas F i r 270° ll 3,090 Middle-aged Douglas F i r 250° 18 3,050 45 3,200 3 3,010 13 2,920 28 2,885 4 2,970 Bitterbrush ' Mature Douglas F i r Young Ponderosa P i n e 5.0°' 0 M i d d l e - a g e d Ponderosa Pine 210° C l i m a x Ponderosa P i n e 260° Lodgepole P i n e 0 E s t e l l a Mountain S e r a i Bunchgrass 240° 6o 6,200 S e r a i Fescue 260° 47 5,950 R e g e n e r a t i n g Douglas F i r 290° 5 4,170 Larch 280° 33 4,220 Lodgepole P i n e 260° 45 5,980 APPENDIX Key to the s i t e s on 1 Mature Douglas f i r 2 Young D o u g l a s f i r 3 Middle-aged Douglas f i r 4 Young p o n d e r o s a 5 Middle-aged pondrosa 6 Lodgepole 7 Poa-Stipa (unforested) 8 Bitterbrush 9 Bluebunch wheatgrass II P r e m i e r R i d g e , map pine pine pine (Purshia) unforested unforested on n e x t page. 135 APPENDIX I I I • . L i s t o f p l a n t s found on t h e study- a r e a s ; common and s c i e n t i f i c names l i s t e d . S c i e n t i f i c Name Common Name Grasses Agropyron s p l c a t u m v a r . inerme B e a r d l e s s wheatgrass o r bluebunch wheatgrass• Bromus t e c t o r u m Downy brome, downy chess Festuca Rough f e s c u e scalrella Koeleria cristata Junegrass Poa compressa Canada b l u e g r a s s Poa p r a t e n s i s Kentucky b l u e g r a s s Stipa Columbia columhiana needlegrass Stipa rlchardsoni Richardson needlegrass Stipa williamsonli Williams needlegrass Forbs Achilles millefolium Yarrow A l l i u m cernnum Nodding o n i o n Anaphalls margarltocea Anemone mult.if i d a Globe anemone Anemone patens Pas que f l o w e r • A n t e n n a r i a racemosa A r a b i s drummondii Drummond's r o c k e r e s s Arnica Heart-leaf arnica cordifolia Aster consplcuus ' Large p u r p l e a s t e r o r showy aster Astragalus miser Timber m i l k v e t c h 137 Balsamorhiza Calochortus sagittata elegans Spring sunflower Elegant mariposa lily Calochortus macrocarpus Green banded mariposa Calypso F a l s e lady bulbosa Componula r o t u n d i f o l l a Bluebell Carex Various spp. Castille.ja minlata Crepls slipper sedges Indian p a i n t b r u s h atrabarba Ep 1 lob ium minatum E r i g e r o n compos!tus Erigeron Fleaban e fillfollus E r i g e r o n speceosus Eriogonum umbellaturn Sulphur eriogonum Galliardia arstita Blanket flower Gent1ana a m a r e l l a Geum t r i f l o r u m Hedysarum sulphurescens Hieraclum albiflorum Hierocium umbellaturn White hawkweed Lesquerella Douglasii Lewisia red!viva B i t t e r root Linum l e w i s s i Wild Lithospermum r u d e r a l e Puccoon Lomatium macrocarpum flax 138 Lomatium triternatum Oxytropxas compestrls Narrow-leaved Locoweed Penstemon p r o c e r u s Little Phacelia Mountain Phlox servicca caespitosa parsley flower Tufted penstemon phacelia phlox PolemonIum p u l c h e r r i m u m Pyrola. secunda Sedum s p p . Senecio Stonecrop canus Sisyrlnchium spp. Saildago Blue eyed grass multirudiata Stenonthlum Occidentale Bronze bells Trapapogon dublus Oyster plant V i o l a , a dune a Blue Zygadenus Mountain death elegans Zygadenus yenenosus violet camas D e a t h camas Dwarf Shrubs Amelanchier Berberis alnifolia. nervosa Saskatoon b e r r y Mahonia o r Oregon g r a p e Linnaea b o r e a l i s Twin R o s a gymnoca.rpu Dwarf r o s e Spiraea Flat-top lucidea. (serviceberry) flower spiraea 139 Other Shrubs Arctostaphylos Uva-ursl Kinnikinnik C l e m a t i s Columbiana Blue clematis Phlladelphus Mock orange Purshia lewisli tridentata Shepherdia canadensis Symphorlcarpus a l b a or bearberry Bitterbrush Soapoiallie, Snowberry bearberry
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Secondary autogenic succession in the southern Rocky Mountain Trench Kemper, John Bryan 1971
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Title | Secondary autogenic succession in the southern Rocky Mountain Trench |
Creator |
Kemper, John Bryan |
Publisher | University of British Columbia |
Date Issued | 1971 |
Description | The patterns and rates of forest regeneration on a critical wildlife winter range on the floor of the trench, known locally as Premier Ridge were examined in this study. A nearby western wall of the trench was also investigated to ascertain the effect of elevation on forest regeneration and understory productivity. Forest regeneration in a community which has remained unforested for several as years has pronounced effects on the floristic dynamics and productivity of the understory. On Premier Ridge the greatest floristic change was a rapid increase in pinegrass and a. corresponding decrease in the abundance of all other grass species as the forest regeneration progressed. Forbs varied widely in abundance while shrubs were slower to react to changes in the overstory. Similar trends were observed on Estella Mountain. Productivity of the grass component on the unforested sites was four times that of the forested sites. The production of forbs and some species of shrubs also declined as forest regrowth began. One species, bearberry, increased under light forest canopies. The reduction in productivity and the changes in species composition of-the understory which occur in regenerating forest communities, appear to be detrimental to foraging populations of wild and domestic ungulates. Cattle seem to prefer to graze the open, unforested areas, and as regeneration proceeds, the acreage which they will readily use diminishes. Since there have been few reductions in stock numbers to compensate for this range shrinkage, local overgrazing has become more widespread. The regrowth of the forest reduces the grass, both in terms of quality and quantity. This is the most important component in the diet of cattle and most of the wildlife species using the Premier Ridge area. In addition, bitterbrush, used in the summer by cattle and during the winter by big game species, is quickly eliminated by forest regeneration. Bearberry, which may be used by wildlife to some extent, increases under forest cover. This component does not approach in value or usefulness, the losses that the other components represent to grazing animals. The trees of the south and southwestern aspects are characterized by relatively slow growth rates. Forage production on these slopes is modest; if grazing animals are deemed desirable in the future economy of the East Kootenay, these areas should remain treeless. Growth rates are more favourable on the north and northeast aspects, which are less frequently used as foraging areas by winter wildlife, but may be used as shelter or bedding areas. |
Subject |
Forest regeneration Forests and forestry -- British Columbia -- Rocky Mountain Trench |
Genre |
Thesis/Dissertation |
Type |
Text |
Language | eng |
Date Available | 2011-04-29 |
Provider | Vancouver : University of British Columbia Library |
Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
DOI | 10.14288/1.0093297 |
URI | http://hdl.handle.net/2429/34141 |
Degree |
Master of Science - MSc |
Program |
Plant Science |
Affiliation |
Land and Food Systems, Faculty of |
Degree Grantor | University of British Columbia |
Campus |
UBCV |
Scholarly Level | Graduate |
Aggregated Source Repository | DSpace |
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